Glossary of electrical and electronics engineering

Short description: List of definitions of terms and concepts used in electrical engineering and electronics

This glossary of electrical and electronics engineering is a list of definitions of terms and concepts related specifically to electrical engineering and electronics engineering. For terms related to engineering in general, see Glossary of engineering.

Template:TopicTOC-Electrical engineering

A

AC adapter: An external power supply for portable devices that allows them to operate from wall-socket electricity.
AC power plugs and sockets: Electrical connectors used with alternating current.
AC power: Electric power where the current reverses direction periodically.
AC-to-DC conversion (rectifier): Rectification of AC current, so that current flows in only one direction.
AC-to-AC converter: A power converter where the input and output are both in the form of alternating current (AC), but may differ in frequency or other characteristics.
AC/DC receiver design: A radio receiver that can operate from either alternating current or direct current wall socket power.
active rectification: A circuit where rectifier devices are externally controlled to change AC to current flowing in one direction.
actuator: An end device of a control system that manipulates a physical variable such as a valve opening or the position of a machine part.
adaptive control: A control strategy where parameters are adjusted as the controlled process changes.
additive white Gaussian noise: A noise model that is used in telecommunications to model the effects of various random processes.
adjustable-speed drive: Control for a motor that allows more than one speed to be selected.
advanced z-transform: A mathematical technique used to model and analyze digital systems.
affinity laws: Mathematical formulas that relate the speed, flow, and diameter of pumps, fans, blowers, and turbines, useful for predicting output under varying conditions.
agbioeletric: A brand name of a kind of vegetable oil for use in transformers.
AIEE: American Institute of Electrical Engineers, predecessor organization to IEEE.
alpha–beta transformation: A mathematical technique useful in analysis of three-phase circuits.
alternating current (AC): Electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows in only one direction.
alternator: An electrical machine that converts mechanical power into AC electric power.
alternator synchronization: The process of synchronizing an alternator to a grid or to another alternator.
aluminium smelting: The reduction of aluminium ore to metal, by use of large amounts of electric power.
ammeter: An instrument that measures electric current.
amorphous metal transformer: A power transformer where the metallic core is made of metals cooled so quickly that they do not form a crystal structure; such transformers can reduce some kinds of energy loss.
ampacity: The current-carrying capacity of a conductor, in the context of electric power wiring.
ampere (A): The SI unit of electric current, equal to one coulomb (C) passing a given point in an electrical circuit per second.
Ampère's circuital law: The mathematical relation between the integral of the magnetic field over some closed curve to the current passing through the region bound by the curve.
Ampère's force law: The mathematical relation between the force between two current-carrying conductors and the current flowing in them.
Ampère's law: See Ampère's circuital law.
amplidyne: An electric machine that allows a small current to control a much larger current.
amplifier: A system that produces an output that replicates an input signal but with a larger magnitude.
amplitude modulation: Transmission of information by changing the magnitude of a carrier signal, for example sending sound by radio.
analog circuit: A circuit where currents and voltages vary continually within some practical range, in proportion to some signal.
analog filter: An analog circuit that alters some frequency-related property of a signal.
analog signal processing: Generally, techniques used to alter signals that rely on voltages or currents that vary continually over a practical range.
analog signal: A signal whose properties (current, voltage) vary proportionally to the information transmitted.
analog-to-digital converter: A circuit that produces a number proportional to the magnitude of a voltage or current.
anode: The terminal of an electrochemical or electronic device through which conventional current flows inward.
antenna: A structure which converts between electromagnetic waves in space and currents in a conductor.
apparent power: In an alternating current power circuit, the product of the magnitude of RMS voltage and current.
Apple Inc. (formerly known as Apple Computer): A company that makes mobile telephones and computers.
arbitrary waveform generator: A type of signal generator that can generate almost any waveform.
arc converter: A device once used to generate radio waves.
arc furnace: A furnace that melts materials with the intense heat produced by an electric arc.
arc lamp: An electric lamp that generates visible light from an electric arc.
arc welder: A device used to join metals by melting them with the intense heat produced by an electric arc.
armature: That part of an electrical machine that converts electrical energy to mechanical energy (or vice versa).
artificial intelligence (AI): A computer system that replicates some feature of human intelligence.
artificial neural network: A network of individual logic elements in multiple layers that mimics the functions of a biological nervous system; a technique in artificial intelligence.
asymptotic stability: A condition of a control system where the output eventually reaches a steady-state value in response to any input.
asynchronous circuit: A digital circuit where states propagate through a circuit without a synchronizing clock impulse.
audio and video connector: An electrical fitting used to connect cables carrying audio or video signals.
audio equipment: Equipment used to handle signals at frequencies within the human range of hearing.
audio filter: A circuit intended to alter some frequency-related property of a signal carrying sound information.
audio frequency: A signal whose frequency is within the range of human hearing.
audio noise reduction: Reduction of interfering signals in an audio signal.
audio signal processing: Alteration of any properties of a signal carrying sound information (dynamic range, frequency response, or others).
audion tube: An early three-electrode vacuum tube that had amplifying properties.
Austin transformer: A kind of isolation transformer.
automatic gain control: A circuit that automatically adjusts the magnitude of a signal to prevent it from becoming too small or too large.
automatic transfer switch: An electrical switch used to automatically select a standby source of electrical power when the principal source is lost.
automation: Automatic control of a process.
autorecloser: A circuit protection device for overhead power distribution lines which briefly interrupts a circuit when a fault is detected, then restores the circuit in the expectation the fault has cleared.
autotransformer: A transformer where the primary and secondary circuits share some of the transformer windings.
availability factor: The fraction of time that a power plant is available to produce power.
avalanche diode: A diode intended for regular operation in the reverse, avalanche breakdown, mode. Used as a voltage reference, noise source, and in certain classes of microwave oscillator device.
average rectified value: The average value of an alternating current waveform, taking the absolute value of the waveform. The average value is generally different from the root-mean-square value.

B

backward wave oscillator: A type of micowave oscillator vacuum tube.
balanced line: A transmission line with two conductors, with equal impedances to earth ground.
ball bearing motor: A conceptual motor that does not use electromagnetism.
balun: A device that connects a balanced transmission line to an unbalanced line.
band-pass filter: A filter that lets through signals within a range of frequencies.
band-stop filter: A filter that blocks signals with a particular range of frequencies.
bandwidth: The range of frequencies over which a system generates or uses significant signal power.
bang-bang control: A controller that switches a final element on or off instead of providing a proportional response.
Barlow's wheel: A demonstration of electromagnetic principles.
Bartlett's bisection theorem: A mathematical theorem used in network analysis.
base load power plant: An electric power plant that furnishes the part of the load that does not vary during a day.
battery: An electrochemical device that produces electric power from chemical reactions.
battery eliminator: An AC adapter, which allows battery operated equipment to run on wall-socket AC power.
Bayer filter: An optical filter used in color digital cameras.
beam tetrode: A type of vacuum tube with four active elements plus a pair of beam forming plates.
beat frequency: A frequency produced by non-linear mixing of signals at two other frequencies.
Bell Telephone Laboratories: Formerly, the research and development laboratory of the American Telephone and Telegraph Corporation.
biasing: The practice of setting the quiescent operating conditions of an amplifying device to obtain desired response.
BIBO stability: A control system that produces finite outputs for any finite input.
bilinear transform: A mathematical technique to obtain the parameters for a digital filter to duplicate the response of some analog filter transfer function.
bimetallic strip: A temperature-sensing element made of two metals that have different coefficients of expansion which have been intimately bonded together.
Biot–Savart law: The mathematical relationship between a magnetic field and the current producing that field.
bipolar junction transistor: A type of transistor with two kinds of charge carriers.
blocked rotor test: A test of an electric machine where the machine is energized but the shaft is prevented from turning.
Blu-ray: A type of optical disc written and read using a blue/violet laser.
Bode plot: A plot of the amplitude and phase frequency response of a system, where the actual response is approximated by straight-line segments.
Boolean algebra: A type of algebra that deals with values that can only hold values "true" and "false", of great use in design and analysis of digital systems.
boost converter: Any power converter circuit that can produce an output voltage larger than its input voltage.
booster: A device used to increase voltage on an electric power distribution system, such as a motor-generator set on a DC system.
bound charge: Electric charge in a material that is not free to move through the material.
braking chopper: A device used to absorb energy from a motor to slow it down.
branch circuit: In building wiring, any circuit from the main panelboard to utilization equipment or receptacles.
breakdown voltage: The maximum voltage a device can withstand without damage.
bridge rectifier: A set of rectifier diodes used to convert alternating current to direct current.
broadcasting: Transmission of a signal to many receivers.
brush: A sliding electrical contact between a moving part and a stationary part.
brushed DC electric motor: An electric motor with brushes.
brushless DC electric motor: An electric motor without brushes.
Buchholz relay: A gas pressure sensing device for protection of oil-filled transformers.
Buck converter: Any power converter circuit that produces an output voltage less than its input voltage.
Buck–boost converter: Any power converter circuit that can provide a voltage greater or less than its input voltage.
Buck–boost transformer: A transformer that can be used to adjust voltage.
busbar: A set of conductors used to distribute current to many branches.
bushing: An electrical fitting used to connect external conductors to the interior of apparatus.
Butterworth filter: A type of filter with the flattest possible pass band.
buzzer: An electromechanical or electronic device that produces a sound when energized.

C

Canadian Electrical Code: The technical standard for building wiring in Canada.
Canadian Standards Association: Non-profit organization that develops electrical and other technical standards.
capacitance: The ability of a body to hold an electrical charge.
capacitor: An electrical component that stores energy in an electric field.
capacitor-input filter: A power supply network where a capacitor is the first element following the rectifier.
capacitor voltage transformer: In electrical power systems, an instrument transformer for measuring voltage that uses a capacitive voltage divider.
capacity factor: The ratio of energy produced by a power plant over some period, over its maximum possible energy production in that time.
carrier current: A system for communications where a carrier signal is impressed on power line wiring.
carrier wave: A radio wave that can be modulated (changed systematically) to carry information to a receiver.
Category 3 cable: A performance standard for unshielded twisted pair cables for analog voice and low speed data circuits within a building.
Category 5e cable: A performance standard for unshielded twisted pair cables for telephone and data within a building.
Category 6 cable: A performance standard for unshielded twisted pair cables for telephone and high speed data within a building.
catenary: A geometric form of curve, the shape of a uniform cable hanging between two supports.
cathode ray oscilloscope: An electronic instrument that displays the wave shape of electrical signals on a cathode ray tube.
cathode ray tube: A vacuum tube that relies on an electron beam – usually used to render images on a fluorescent screen such as in television sets.
cathode: The terminal of an electrochemical or electronic device from which conventional current exits the device.
cat's-whisker detector: A radio detector that uses a manually-set "whisker" contact to a crystal of galena or other material, to form a rectifying junction.
CATV: Cable television, distribution of television programming over a wire instead of by radio broadcast.
cavity magnetron: A vacuum tube that is a high power microwave oscillator, using a resonant cavity and electrons traveling through a magnetic field.
CD: A "Compact Disc" used to store digital data or digitally recorded sound using an infrared laser.
center tap: A connection on a transformer which has equal voltage to either end of the transformer winding.
ceramic resonator: A piezoelectric element used to stabilize the frequency of an oscillator.
channel: Any communication path between a signal transmitter and a signal receiver, or, a pre-selected operating frequency for a radio system.
channel capacity: An upper bound on the rate at which information can be reliably transmitted over a communication channel.
charactron: A kind of text display vacuum tube that used an internal element to shape an electron beam to represent the shape of letters and other symbols.
charge pump: A DC to DC converter circuit that uses capacitors to store energy between stages.
charge transfer switch: A kind of charge pump circuit.
charge-coupled device: An imaging sensor or data storage device that represents a signal, or pixel, by the charge stored in a capacitor and is able to move that charge from one capacitor to the next.
Chebyshev filter: A form of filter that has a steep frequency selective characteristic.
choke: An induction coil used to block alternating current and pass direct current, or to block high frequencies and pass lower frequencies.
chopper: A circuit that switches on and off at a high rate, used either for power conversion or to convert a DC signal to a more easily processed AC signal.
circle diagram: A representation of the voltage and current characteristics of an electrical machine; the plot traces out a circle or part of a circle.
circuit breaker panel: A distribution board for electric power that uses circuit breakers as protective elements.
circuit breaker: An automatically operated electrical switch that opens to interrupt a short circuit or other fault.
circuit theory: The mathematical theory of electrical circuits.
Circuit Total Limitation (CTL): A US National Electrical Code rule for the number of circuits in a panel board.
clamp meter: An ammeter that measures current with a split core that can be clamped on a wire.
Clapp oscillator: An electronic oscillator circuit that uses three capacitors and an inductor.
class of accuracy in electrical measurements: A measure of the error produced by an electrical measuring instrument.
closed-loop controller: Any controller that manipulates some process variable to minimize the difference between the current state of the variable and the desired set point, such as temperature, flow, or others.
CMOS: Complementary metal–oxide–semiconductor, a fabrication process for MOSFETs and integrated circuits
coaxial cable: A cable with an inner conductor centered inside a flexible tubular conductor, used for radio frequency transmission lines.
Cockcroft–Walton generator: A kind of circuit for generating very high DC voltage.
cogeneration: Production of electricity along with some other desired product, such as process steam or desalinated water.
cold cathode: An element of a vacuum tube that emits electrons without a heating circuit.
Colossus: A British code breaking system used during World War II.
combined cycle: A thermal power plant that improves efficiency with two different kinds of energy extraction from the combustion products gas stream, such as a gas turbine followed by a steam boiler.
communication system: A system intended to convey information from one place to another with an expected degree of performance.
communications satellite: A satellite in Earth orbit designed for international telephone, television, or data transmission.
commutation cell: The elementary switching device in a power converter circuit; it could be a transistor, a thyristor, a mercury-arc valve, or others.
commutator: A component of a DC electric machine that connects the rotating coils with an external circuit through brushes.
compact fluorescent lamp: A fluorescent lamp with a folded or spiral tube, designed to fit in the same space as an incandescent lamp of similar light output.
Compactron: A brand of vacuum tube, used in some radio and television sets, that combined multiple independent functions in one envelope.
compensation winding: A winding on a motor or generator to improve commutation at heavy load.
computed tomography: Production of images of a cross-section through an object by multiple X-ray measurements processed in a computer.
computer engineering: The profession of designing computers.
computer hardware: That part of a computer system with physical existence.
computer programming: The practice of producing instructions for a computer to achieve some desired effect.
computer-aided design (CAD): A design discipline where a computer is used to produce a graphical representation of a real-world object in order to design its structure or to assist in calculating performance parameters.
conduction band: In a conductor, the energy levels of charge carriers that are free to move through the material.
constant k filter: A method formerly used for designing filters for a required characteristic.
consumer electronics: Electronic devices intended to be owned by consumers directly; a mobile cell phone is "consumer electronics" but the cell site it communicates with is not.
contactor: An automatically controlled electrical switch (relay), used to operate motors or other high-current loads.
continuous Fourier transform: A mathematical operation that expresses a signal in time as the sum of its frequency components.
continuous signal: A signal that can take any value within its range.
control engineering: The application of control theory to practical problems.
control system: The equipment used to adjust some parameter of an ongoing process to regulate its behavior to a desired goal, such as positioning a disk drive head or regulating temperature of a furnace.
control theory: The mathematical study of behavior of control systems.
controllability: In control theory, the degree to which a system can be put into any desired state given manipulation of one variable.
controller: A system that adjusts some variable to control a process.
copper cable certification: The process of testing a computer network cable installation to verify that it meets standards.
copper loss: That portion of an electric machine or transformer's loss attributed to the resistance of conductors (which are not necessarily made of copper).
corona ring: A component of a high-voltage system intended to smooth out the electric field distribution around energized parts.
coulomb: The SI unit of electric charge.
Coulomb's law: The mathematical relation between force, electric charge and distance.
CPU: Central Processing Unit, the element of a computer that carries out arithmetic and logic operations.
crest factor: The ratio of peak to effective (RMS) value of a waveform.
crossed-field amplifier: A type of microwave amplifier vacuum tube.
crosstalk: Objectionable presence of a signal from one circuit in another circuit sharing the same transmission path, such as a cable.
crystal oscillator: An electronic oscillator whose frequency is stabilized by a piezoelectric crystal resonator element.
Ćuk converter: One kind of buck-boost voltage converter that uses a capacitor as an energy storage element.
current: The movement of electric charge.
current density: The current flowing per unit area of a conductor.
current source inverter: A type of power inverter where an inductor tends to keep a constant current flowing in the inverter stage.
current source: In circuit theory, an element that produces a defined current independent of the connected circuit properties.
current transformer: An instrument transformer used for measuring current in AC power systems.
current-to-voltage converter: A transducer that produces an output voltage in response to an input current.
cybernetics: The science of automatic control systems.
cycloconverter: A type of variable-frequency power converter that does not first convert AC to DC.

D

damping ratio: A parameter that indicates how rapidly oscillations in a system die out, if ever.
Darlington transistor: An interconnection of two transistors to provide a gain that is the product of the individual gains.
data compression: Any technique that allows information to be transmitted more compactly than originally expressed, for example, codes.
data networks: A network for interconnection of computers and peripherals.
DC injection braking: A method of slowing an AC electric motor by passing direct current through its windings.
DC-to-DC converter: A circuit that converts a DC voltage into a different level of DC voltage.
degaussing: The process of reducing the residual magnetic field in a metallic object, such as a ship.
delay line: A circuit component that introduces a delay in a signal.
delta-wye transformer: One type of connection of a three-phase transformer.
demand factor: The fraction of actual use of some quantity, related to the maximum that could be used in a specified time.
demand response: The ability of a generating station or grid to follow changes in load while maintaining voltage and frequency within acceptable limits.
demodulation: The process of recovery of information (sound, video, data) from a modulated carrier.
describing function: A method for analyzing non-linear control systems.
detector: A circuit that demodulates a radio signal to recover information.
DIAC: A four-layer semiconductor diode that has a predictable breakdown characteristic.
dielectric: A material that does not allow free flow of electric current.
digital audio broadcasting: Transmission of sound by digital signals over radio.
digital circuit: A circuit where all points on the signal path have only one of two states.
digital computers: A computer made of digital circuits.
digital control: A control system that processes signals in digital form.
digital filter: A filter implemented as a digital circuit.
digital image processing: Manipulation of an image by a digital computer.
digital micromirror device: An element of a kind of digital projector system.
digital protective relay: A power system protection device that processes signals in digital form.
digital signal controller: A type of microprocessor that combines a digital signal processor element with a more general purpose microcontroller.
digital signal processing: The technique of modifying the properties of a signal that has been converted to digital form.
digital television: Transmission of images using digital techniques.
digital-to-analog converter: A device that produces a voltage or current that is proportional to a digital value sent to it.
diode bridge: An interconnection of diodes to rectify alternating current to direct current.
diode: A two-terminal passive circuit element, with a preferred direction of current flow.
dipole antenna: A simple form of antenna that consists of two conductors oriented end-to-end with a feed in between them.
direct current (DC): Electric current that flows in one direction only, in contrast to alternating current (AC), where the flow of current periodically changes direction and magnitude.
direct on line starter: A kind of motor starter that does not reduce the voltage at the motor terminals.
direct torque control: A method of estimating motor torque as part of a variable speed motor drive.
discrete cosine transform: A mathematical technique for representing a sampled signal as a sum of cosine waves of different frequencies.
discrete Fourier transform: A mathematical technique for representing a sampled signal as a sum of sine and cosine waves of different frequencies.
discrete-time signal: A signal represented as a time series of samples taken at regular intervals.
displacement current: The effect of a time-varying electric field, which induces a magnetic field just as the motion of electrical charges does.
display device: Any device that displays data from an information system, such as a watch readout or an automatic scoreboard.
dissipation: The loss of energy in a system, such as dielectric loss in a capacitor.
dissolved gas analysis: A technique for fault detection in oil-filled transformers.
distributed control system: A control system in which significant parts of the control process are decentralized.
distributed-element model: An analysis of an electric circuit where capacitance, inductance, and resistance are distributed along the circuit, as in a transmission line, not concentrated in lumped components.
distributed generation: An electrical grid where multiple small sources contribute energy, instead of relatively few large central generating stations.
distribution board: A piece of electrical switchgear which distributes electric power to multiple branch circuits.
distribution transformer: A power transformer, usually used to change the utility distribution voltage to a lower voltage for use on the customer premises.
Dolby: A trademark for a noise reduction technique for analog sound recordings.
dot convention: A system for marking terminals on instrument transformers to maintain correct polarity.
doubly fed electric machine: An electric machine where both moving and stationary elements have external connections handling significant power.
downsampling: A technique for reducing the number of signal samples processed by a digital system; decimation.
Dqo transformation: A technique used to simplify mathematical analysis of polyphase electric circuits.
droop speed control: A method of regulating generators so that multiple units share the load proportional to their ratings.
dual control theory: A branch of control theory that deals with systems whose characteristics are initially unknown.
dual loop: A method of supervising contacts and wiring in a security system, so as to detect some faults or tampering.
DVD: Digital Versatile Disc, a type of optical disc for distributing video recordings and data using an orange/red laser.
dynamic braking: A braking system that extracts energy from a moving system to bring it to rest; a dynamic braking system generally is not used to hold a position of a stationary object.
dynamic demand: A technique for load management on an electrical grid based on frequency measurement.
dynamic programming: A technique for optimization of the solution of a problem by combining solutions to smaller sub-problems.
dynamic random-access memory: A type of semiconductor memory where data is stored as electric charges on capacitors; the charges must be refreshed periodically or else they will leak away, losing the stored data.
dynamo: A direct-current generator, whose exciting field is provided by an electromagnet.

E

earth-leakage circuit breaker (ELCB): A protective device consisting of a current- or voltage-sensing mechanism that opens or "breaks" a circuit when stray current or voltage is detected, which might otherwise present the possibility of electric shock.
eddy current: An electric current induced inside a conductor exposed to a changing magnetic field.
edge detection: An image processing technique used to identify boundaries of objects.
Edison effect: The emission of an electric current from a hot electrode, the thermal energy of which gives some small charged particles such as electrons and ions enough kinetic energy to escape the material's surface. Thermionic emission is the fundamental mechanism underlying the vacuum tube.
electret: A dielectric material that quasi-permanently retains an impressed electrical polarization; the dual to a magnet.
electric arc: The discharge of electric current through an open space between conductors, either intentionally to produce a source of intense light and heat, or as the result of an electrical fault.
electric charge: The physical property of matter that causes it to experience a force when placed in an electromagnetic field.
electric circuit: A closed path through which an electric current can flow.
electric current: The motion of electric charges.
electric displacement field: In Maxwell's equations, a vector field due to electric charges.
electric distribution systems: That portion of an electrical grid that connects customers to substations or the bulk transmission system.
electric field gradient (EFG): The rate of change of an electric field with respect to distance.
electric field: A vector field that exerts a force on electric charges.
electric generator: A machine that converts mechanical energy to electrical energy by moving conductors through magnetic fields.
electric motor: A machine that produces mechanical energy from electrical energy, by moving conductors through magnetic fields.
electric multiple unit: The use of more than one electric locomotive on a train.
electric potential: A measure of the work required to move a unit electric charge in an electric field.; Generally, changing the form of electric power.; In an electric grid, the network that brings power from a substation or bulk supply to individual customers.; A non-profit organization that carries out research on behalf of the US electric power industry.; The bulk movement of electric power for many customers from a generating plant to a local distribution network, usually at high voltage.; The rate of transfer of electrical energy past a given point.; An injury caused to people or animals by electric current.; A flexible conducting wire to carry electrical power or signals, usually covered with an insulating material.; A set of regulations for the use of electricity; they may vary from municipal to international in scope.; A measure of a substance's ability to pass an electric current.; An object that carries an electric current, with little loss.; A separable part of an electric device that carries current when touching another contact.; Shaping of a workplace by small sparks.; In circuit theory, a node at which some electrical property is concentrated (resistance, etc.).; The profession of applying electricity to practical problems.; Any apparatus for generation, transmission or utilization of electric power.; A geographically distributed system to connect sources and users of electric power.; That property of a circuit that resists the passage of electric current, usually in the context of alternating current.; A grade of paper used for insulation of transformers, electrical machines, capacitors, and some cables.; A material that resists electrical current flow.; A consumer of electrical energy, turning it into light, heat, mechanical power, data, or chemical changes.; Any apparatus that converts between electrical power and mechanical power, such as a motor or generator.; That branch of metrology concerned with electrical quantities.; A network of electrical components and conductors.; Identification of electrical terminals where current is flowing in the same direction relative to the device.; Any of several types of steel used for manufacturing the magnetic field components of machines and transformers.; A facility connecting a distribution network to a transmission network, usually with one or more transformers.; A specialist in applying electrical theory and technique to practical problems.; The legal framework for electrical installations in buildings.; The installation of conductors, fixtures and protection devices for a structure or vehicle.; An instrument to measure the electrical energy used by a customer for revenue purposes.; A structure, generally of wood or metal, to support wires.; The set of physical phenomena associated with electric charges.; Applying electric power to a process that was previously done by other means, or, development of an electric power system in a region that previously had none.; A polymer that significantly changes size or shape when exposed to an electric field.; A record of the electrical activity of the heart.; The profession of application of electrochemistry to practical problems.; An electrical contact that connects some medium to an electric circuit, such as in an electrochemical cell or a vacuum tube.; A railway locomotive with a diesel engine, generator, and electric driving motors that can be powered by the diesel engine or the track electrical supply.; The branch of physics that studies electrical charges and electrical currents.; A liquid or solid medium that carries electric current in the form of ions.; A magnet that generates a magnetic field from an electric current.; The control of unwanted electromagnetic interference.; The field produced by moving electric charges and magnetic fields.; The production of current in a circuit by the change of magnetic field intersecting the circuit.; Radio waves, light and other radiation that travels through space at the speed of light.; The range of frequencies of electromagnetic radiation.; A second-order partial differential equation that describes the propagation of electromagnetic waves through a medium or in a vacuum.; The science of electric fields, magnetic fields, currents, charges, and forces.; A system that has both an electrical component and a mechanical component, such as a motor or a relay.; An 1882 demonstration of a prototype electric trolley bus.; A difference in electrical potential between two points, such as produced by a battery or a generator.; An instrument that provides highly magnified images by use of an electron beam.; A device that increases the power of an electrical signal by electronic means.; A circuit using one or more electronic devices.; An active or passive element of an electronic circuit.; In an automobile, an embedded electronic system that controls some aspect of a vehicle (ignition, transmission, and so on).; A system in which a computer provides assistance to the designer of a device or system.; The profession of applying electronics to practical problems.; A filter that alters some frequency-related characteristic of a signal.; The study of the flow of electrons through a vacuum, gases, or semiconductors.; A device for regulating the speed of a motor.; An instrument used to produce electrostatic charge through electrostatic induction.; A motor that relies on the forces generated by electric fields, instead of magnetic fields.; The study of stationary electric charges and resulting forces.; The common operating environment that supports embedded software; it may be a highly tailored version of a general-purpose operating system, or written solely for the purpose of embedded system operations.; A firmware component of a microprocessor-controlled system.; A computer system that controls a device or system, with no or a minimal user interface; for example, the ignition system in a car may have a microprocessor to control it.; Wire insulated with a thin flexible layer of enamel, used for electrical windings.; A system to adjust energy demand to reduce costs.; A branch of economics concerned with energy supply and demand.; A power transformer designed to have lower than average energy loss.; A measure of how long an energy producing system takes to replace the energy it took to make it.; Payments to a consumer or producer of electric energy that are used as incentives for production or consumption.; A combination of an internal combustion engine and a generator, often used as a standby power plant.; The first general purpose electronic digital computer.; An apparatus used for testing of magnetic materials.; 1. (audio) The adjustment of the frequency response of an audio system to improve its utility.; 2. (communications) The adjustment of the frequency spectrum of a communications signal to cancel out the effect of the frequency response of a communication path.; In circuit theory, a simple combination of elements that behaves at its terminals like a more complex combination.; A mathematical method to determine values of an equivalent circuit.; Techniques used to improve reliability of computer memory or communications channels by including extra information along with the desired data.; A system that settles to a steady state after a disturbance, at a rate proportional to exponential time.; A strategy for estimating an unknown value in a non-linear system by combining multiple measurements.

F

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">farad

The SI unit of capacitance.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Faraday shield

A solid conductive shield around a volume, which blocks electromagnetic fields.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Faraday–Lenz law

One of Maxwell's equations, describing the relation between a changing magnetic field and production of an electromotive force.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Faraday's law of induction

The relation between a changing magnetic field and the resulting voltage produced in a closed path.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">fast Fourier transform

A digital algorithm to analyze a time series of sampled data into a set of sine and cosine frequency components.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">fault

A short circuit, open circuit, or other disruption of a power system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">fax

Lua error: Internal error: The interpreter has terminated with signal "24".

The transmission of paper images by radio or by wire.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">feed forward

A control system that adjusts the controlled variable based on a model of the process and measurements of disturbances, instead of feedback from measurement of the process.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">feedback amplifier

An amplifier that feeds back a small sample of its output to its input, to improve linearity.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">feedback

A system that samples part of its output and adds that to its input; feedback may be either positive or negative, aiding or opposing the initial input signal.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">feed-in tariff

A premium rate paid to distributed generators to encourage alternative energy sources.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ferrite core

A magnetic core for an inductor made from a metal oxide compound.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ferroelectricity

The property of materials that spontaneously maintain an electrical polarization, as a ferromagnetic material maintains magnetic polarization.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">fiber-optic cable

A transmission medium that uses infrared energy or light to transmit information down a long thin transparent filament such as glass.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">field effect transistor

A transistor that relies on modulation of conductivity of a channel instead of injection of minority carriers as does a bipolar transistor.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">field-oriented control

A control strategy for variable frequency drives that models the magnetic field of the motor to control its torque.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">filter

A circuit that selectively alters a signal based on its frequency components.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">filter capacitor

In a power supply, a capacitor that smooths the DC voltage produced by a rectifier stage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">finite impulse response

A class of digital filters whose response to an impulse returns to zero in finite time.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">firmware

Software of a computer that is never or rarely altered during its working life, for example, the control computer program for an automotive ignition system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Fleming valve

The first important vacuum tube device, used as a radio detector.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Fleming's left-hand rule for motors

A mnemonic to recall the relative orientation of current, magnetic field and resulting force for electric motors.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Fleming's right-hand rule for generators

A mnemonic to recall the relative orientation of current, magnetic field and resulting force for electric generators.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">fluorescent lamp

A type of electric lamp that relies on a phosphor coating to produce visible light from the ultraviolet light generated by a mercury discharge.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">flux linkage

In a magnetic system, that part of the magnetic flux that passes through a given closed path, which may be a winding.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">flyback converter

A type of voltage converter that stores energy in an inductor.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">flyback transformer

A type of transformer that recovers energy stored in its own core. Historically used in the deflection circuits of CRT display systems.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">forward converter

A type of voltage converter that relies on transformer action to couple energy to its output circuit.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">fossil-fuel phase-out

A plan to replace coal, oil, or natural gas fuel with other sources to produce electrical energy.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">fossil-fuel power station

A power plant using coal, oil, or natural gas fuel.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Fourier series

A set of coefficients of sine and cosine waves; this can represent a time function as a function of frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Fourier transform

An algorithm for converting a continuous waveform in the time domain into an equivalent set of spectral components in the frequency domain.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">free space optical communications

Transfer of information from point to point by a beam of light or infrared energy, instead of a wired connection or radio waves.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">frequency changer

An electric machine used to transfer power between two networks with different frequencies, or, an electronic device (more usually called a frequency mixer) that changes the frequency of an input signal to some other frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">frequency modulation

A method of impressing information on a carrier wave by changing its frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">frequency response

The measure of the output of a system in response to an input of varying frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">full load current

The current drawn by a motor or other electrical machine at its full rated power and standard voltage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">full-wave rectifier

A rectifier circuit that converts both positive and negative parts of the input alternating current waveform into a unidirectional, direct current.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">fuse

A circuit protective device that interrupts excessive current by melting a metal strip.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">fuzzy control

A control system that relies on fuzzy logic instead of binary true/false conditions.

G

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">gain scheduling

A technique for control of non-linear systems that use different control parameters based on some measurement of the process controlled.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">galvanic corrosion

Electrochemical corrosion of one metal in contact with another.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">galvanometer

An instrument for detecting small electric currents.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">gamma ray

Electromagnetic radiation with wavelengths shorter than ten nanometres; strictly speaking, radiation that is produced in the nucleus of atoms.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">gas-filled tube

An electron tube device that relies on the presence of gas for operation, usually at less than atmospheric pressure.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">gate turn-off thyristor (GTO)

A four-layer power semiconductor device that can be turned on and off by signals at a control (gate) terminal.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Gauss's law

A mathematical relation between the electric flux passing through a surface and the charge contained within that surface.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">generator

In circuit theory, an ideal voltage source or an ideal current source, whose properties are independent of the connected circuit.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">governor

A speed regulator for a machine such as a steam engine; an early important feedback control cybernetic system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">grid energy storage

Any system tied to an electrical grid that stores electrical energy at low demand times and releases it to meet peak loads; it might be a centralized station like a pumped-storage hydroelectric plant, or might be distributed over many customer sites such as by the use of electric vehicle batteries.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">grid-tie inverter

A power inverter that allows synchronization with the electrical grid for export of energy surplus to the facility's needs.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ground

A reference point for electrical potential; often connected to the Earth.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ground and neutral

Protective and circuit return conductors in a wiring system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ground fault circuit interrupter (GFCI)

See residual-current device.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ground-level power supply

A system for providing powers for electric trams without overhead wires and without a permanently energized third rail.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">growler

A test instrument that is used to diagnose some faults with AC motors.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">GSM

The second generation of cellular mobile phone technology, deployed since 1991 in Europe.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Gunn diode

A two-terminal solid-state device that is used in microwave oscillators.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">gyrotron

A high-power vacuum tube oscillator that can produce microwave frequencies up to hundreds of gigahertz at power levels up to megawatts.

H

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">H infinity

An optimization strategy for certain classes of control problems.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Hall effect sensor

A device that detects and measures magnetic field by the Hall effect voltage induced in a current-carrying semiconductor.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">harmonic distortion

An effect of a non-linear signal path that introduces frequencies that are integer multiples of an input frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">harmonic oscillator

An oscillator which produces sinusoidal output, such as a simple RLC oscillator.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">harmonic

A waveform that has a frequency which is an integer multiple of another frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">harmonics

Distortion of the power line voltage due to non-linear loads such as rectifiers.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">H-bridge

An array of four controlled switches that converts direct current to alternating current, with peak value equal to the supply voltage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">HDTV

High Definition Television, any television system with more than 625 scan lines.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">headphone

An audio transducer or pair of transducers designed to be worn on or in the ear.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">heat transfer

The study of the flow of heat energy; heat transfer concerns dictate major design features of most electrical and electronic systems.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">heatsink

A structure intended to dissipate heat from an active device into the ambient environment.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Heaviside step function

A mathematical unit step function useful in the solution of certain differential equations by the methods of operational calculus.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Helmholtz coil

An arrangement of coils useful for producing a uniform magnetic field within a certain volume.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">henry

The SI unit of inductance.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">hertz (Hz)Lua error: Internal error: The interpreter has terminated with signal "24".

The SI unit of frequency, equivalent to one cycle per second (1/s or s^-1).

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">heterodyne

A signal frequency created by combining or mixing signals of different frequencies in a nonlinear signal-processing device such as a vacuum tube, transistor, or diode in order to produce a new frequency. The process of creating such a frequency is called heterodyning; it is used to shift signals from one frequency to another and also as part of the processes of modulation and demodulation.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">heterostructure

A semiconductor device built of two or more dissimilar materials.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Hi-Fi

High Fidelity, the set of techniques for reproduction of sounds that appear natural in source.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">high-voltage cable

A flexible insulated electrical conductor designed to withstand a significant voltage; "high" voltage may be hundreds or hundreds of thousands of volts, depending on the context.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">high voltage

Any voltage at which safety concerns apply. In some contexts, anything over 100 volts may be considered high voltage; in electric power transmission, high voltage usually refers to voltages greater than 66,000 volts.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">high-pass filter

An electrical network that tends to pass higher frequencies and block lower ones.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">high-voltage direct current

A system for power transmission that uses high DC voltages for reasons of economy or stability.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">high-voltage switchgear

Electrical apparatus designed for control of high-voltage circuits.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Hilbert transform

A mathematical operation used in signal processing.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">holography

The technique of recording and reconstructing the wavefront of an electromagnetic field. It is commonly used to generate three-dimensional images known as holographs by recording the interference patterns of light waves as they collide with a physical object or scene, but also has applications in data storage, microscopy, and interferometry.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">home appliance

Any electrical appliance intended for use in a home.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">homopolar generator

A generator in which current and magnetic field direction are constant as the machine rotor revolves.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">homopolar motor

A motor that produces torque from a current and magnetic field that does not change direction.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">horsepower (hp)

A unit of power equivalent to approximately 746 watts.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">hot wire barretter

A current dependent resistor formed of a fine wire in an envelope, useful for regulating current.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">humidistat

A switch that operates automatically on detecting a change in moisture content of the air.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">HVAC

High Voltage Alternating Current; depending on context, this could be hundreds or hundreds of thousands of volts.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">HVDC converter station

An element of a high-voltage direct current power transmission system in which each end of the transmission line has a converter station connected to the local AC grid.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">HVDC

High Voltage Direct Current.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">hybrid coil

A kind of transformer used for bidirectional transmission of signals over one pair of wires, for example, as in an analog telephone set.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">hydroelectricity

The generation of electric power from the kinetic energy of falling or moving water.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">hydropower

Any power (usually electric) generated by the force of moving water.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">hysteresis

A characteristic of a system where its state is history-dependent.

I

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">IGBT

Insulated Gate Bipolar Transistor, a power semiconductor device that combines some of the advantages of field-effect and bipolar transistors.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">image impedance

A parameter used in the design of electrical networks such as filters.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">image noise reduction

Any technique used to reduce interfering effects in processing of an image.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">image processing

Electronic recording, storage, alteration, and reproduction of pictures.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">impulse response

The response of a network to a sudden narrow pulse input.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">incandescent light bulb

A device that uses a fine wire filament heated by an electric current to produce visible light (with heat usually produced as a byproduct).

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">induction coil

An early name for a transformer; or a type of transformer intended for high-voltage uses.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">induction cooker

A cooking appliance that heats pots with magnetic fields by electromagnetic induction.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">induction generator

A type of generator where the rotating field winding is excited by induction from the stationary armature winding.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">induction motor

A type of motor where the rotating field winding is excited by induction from the stationary armature winding.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">induction regulator

A type of variable transformer that provides stepless control of the output by changing the coupling between two coils.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">inductive coupling

The transfer of energy between two circuits through a shared magnetic field passing through both.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">inductive output tube

A high-power, high-frequency amplifier tube, in some forms capable of megawatt pulses at hundreds of megahertz.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">inductor

Lua error: Internal error: The interpreter has terminated with signal "24".

A passive two-terminal circuit component with a concentrated inductance, usually an insulated wire wound into a coil, which stores energy in a magnetic field when an electric current flows through it.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">industrial and multiphase power plugs and sockets

Electrical fittings used to connect cables to three-phase power circuits.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">industrial automation

The general practice of automatic control applied to industrial operations.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">infinite impulse response

A filter which, mathematically, never gets to a zero effect of an impulse at its input, though practically the response may become negligible after a definite time.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">information appliance

Conceptually, an embedded computer system with a specialized user interface designed to simplify one task, such as e-mail or photos; a modern smartphone approaches this concept.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">information theory

The mathematical study of information.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">information

In one sense, the answers to uncertainties.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">input/output (I/O)

That part of a computer system devoted to exporting and importing data, for example, in human-readable form.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">inrush current

The transient current that flows when first connecting a device to a power source.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Institute of Electrical and Electronics Engineers (IEEE)

The American-based society for electrotechnology.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Institution of Engineering and Technology

The British society of electrical and electronics engineers.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">instrumentation engineering

The profession dealing with development of measuring systems.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">instrumentation

A device that turns some physical property into a measurement.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">insulation monitoring device

A supervisory device to detect failure of electrical insulation.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">insulator

A substance that does not permit easy flow of electric current; a fitting intended to support a conductor.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">integrated circuit

An interconnected array of electronic devices, factory assembled on a single substrate.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">intelligent control

The application of artificial intelligence techniques to process control.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">intelligent transportation system

The application of information technology to manage some aspects of a transportation system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">intermittent energy source

An energy source whose availability is transient and not under human control. It may be sporadically available or available on some natural schedule not coincident with human demands. The term refers particularly to energy sources that are not dispatchable.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">International Electrotechnical Commission (IEC)

An international standards organization devoted to electrical standards; most countries are members.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">International Organization for Standardization

An international organization coordinating the efforts of national technical standards organizations.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">interrupter

Any of a series of automatically operated electromechanical switches that periodically open and close a circuit.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">inverter

Lua error: Internal error: The interpreter has terminated with signal "24".

Any electronic device or circuitry that converts direct current (DC) to alternating current (AC) without the use of rotating machines, instead using electron devices such as mercury arc valves or thyristors. An inverter is the opposite of a rectifier.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">iron loss

That portion of the wasted power of a machine or transformer attributed to hysteresis and eddy currents in the iron core.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">isolated-phase bus (IPB)

Lua error: Internal error: The interpreter has terminated with signal "24".

A bus where each phase is in its own grounded metal enclosure to prevent faults from spreading from phase to phase. This design is often used for circuits carrying very large currents such as hydroelectric power plants.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">isolation transformer

A transformer especially intended to prevent leakage current from passing from its primary circuit to the secondary circuit.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">iterative learning control

A technique for improving the accuracy of control systems that carry out the same sequence repeatedly.

J

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">j operator

Electrical engineering uses "j" to represent the imaginary unit "i", to prevent confusion with the symbol for current.

j \times j = - 1

.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Jedlik's dynamo

An early form of electric generator using electromagnets.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">JFET

A field effect transistor with a reverse-biased PN junction between gate and channel.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">jitter

Deviation from the true periodicity of a periodic signal.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Joule heating

Heating in a conductor due to passage of current.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">joule (J)

A derived unit of energy in the International System of Units,^[1] equal to the energy transferred to (or work done on) an object when a force of one newton acts on that object in the direction of the force's motion through a distance of one metre (1 newton-metre or N⋅m). It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second.^[2]^[3]^[4]

K

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Kalman filter

An algorithm for estimating an unknown value from a series of approximate measurements.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Kelvin–Stokes theorem

A theorem in calculus, useful in analytic solutions of problems in electromagnetism.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Kilovolt-ampere

A unit of apparent power.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Kirchhoff's circuit laws

The observation that the sum of the currents at any node of a circuit must be zero, and the sum of the voltage differences around any loop must be zero; often abbreviated "KCL" and "KVL" in lecture notes.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">klystron

A type of microwave oscillator vacuum tube.

L

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ladder network

A string of many, often equally dimensioned, impedances connected between two reference voltages.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">LAN

Local Area Network, an interconnection of computers over a building or small campus.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Laplace transform

A mathematical operation for solution of differential equations by transforming them to the s domain from the time domain.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">laser diode

A semiconductor device that produces coherent laser radiation when properly energized.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">leakage inductance

The inductance of a transformer that results from magnetic flux not linked by both primary and secondary windings.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">light-emitting diode (LED)

A semiconductor device that produces visible, infrared, or ultraviolet light radiation when properly energized.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">linear alternator

An electrical machine that generates electric power from the relative straight-line motion of its parts.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">linear motor

An electrical machine that generates electric force in a straight line by the interaction of its moving parts and magnetic fields.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">linear variable differential transformer

A transducer that produces an electrical signal proportional to the movement between its parts.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">lineman

A specialist technician who installs outdoor plant wiring such as overhead circuits and power transmission lines.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Litz wire

A kind of stranded wire used to minimize losses in coils.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">load flow study

A mathematical prediction of the flow of electric power in a network, based on a model of the actual or proposed system; necessary for planning of electrical grids.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">load following power plant

A power plant that can economically be operated over a significant range of output, so as to meet varying electric power demand.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">load-loss factor

A factor for estimating energy lost in a distribution network due to load current.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">load management

Any strategy for altering the operation of customer loads so as to reduce peak demand on an electrical grid.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">load profile

The daily, weekly, or annual plot of electrical load against time.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">local positioning system

A navigation system that does not cover the whole Earth but rather a particular subregion or locality, which may range in size from an entire continent to a single building.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">LORAN

A radio navigation system developed from a World War II military system (GEE) and used for civilian purposes until the 1980s.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Lorentz force law

The mathematical relation between currents in conductors and the resulting magnetic forces between them.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">lossless data compression

Any data compression method where the source can be reconstructed exactly; where approximations are tolerable, lossy data compression can be used.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">lossy data compression

Any data compression method which allows only a close approximation of the source to be reconstructed; useful for images or music, where the human perceptual system compensates for errors or missing information.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">loudspeaker

An electroacoustic transducer that converts electrical current into sound with amplification that makes it perceptible to more than one listener.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">low-noise amplifier

In a satellite radio receiving system, an amplifier placed near the antenna.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">low-noise block downconverter

In a satellite radio receiving system, a device that amplifies and converts signals to a lower frequency band that will have lower losses in interconnecting cables.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">low-pass filter

An electric filter network that passes lower frequencies and blocks higher ones.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">LTI system theory

The theory of systems that, over a useful range, respond proportionally to inputs and don't change characteristics while responding.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">lumen

The SI unit of luminous flux, the energy of visible light.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">lumped parameters

A set of parameters which describe an electrical network where the circuit elements are small compared to the wavelengths of the signals passing through it.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Lyapunov stability

A criterion for stability of a dynamical system. If disturbances from a stable point decrease and the system returns to that stable point, it can be said to be Lyapunov-stable.

M

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">machine learning

The set of artificial intelligence techniques for systems that can follow examples to solve new problems.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnet wire

The class of wire manufactured for winding electromagnetic coils such as in motors or transformers.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetic blowout

A component of a switching device that uses a magnetic field to assist in extinguishing the arc, using a permanent magnet or a coil.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetic circuit

A path through which magnetic flux passes.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetic constant

The constant that relates the strength of magnetic flux to magnetic induction in free space.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetic core memory

A type of computer memory that stores data as magnetization in tiny rings of ferrite material.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetic field

A field that causes magnets and currents to experience forces.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetic flux density

The amount of magnetic field per unit area; in SI units, measured in webers per square metre.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetic flux

The magnetic field; a conductor that encloses a changing magnetic flux will have a voltage induced in it.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetic moment

The proportionality constant that relates the twisting torque produced on an object to the magnetic field.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetism

The class of natural phenomena related to magnets and magnetic fields.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetization

A property of a material that measures its response to a magnetic field.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetization current

In a transformer, that portion of the current used to support magnetic flux.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetostatics

The study of stationary magnetic fields.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnetostriction

A property of some materials that change shape when subject to a magnetic field.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">magnifying transmitter

A concept for a signal transmitter that used a resonant transformer to provide a high voltage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">main distribution frame

In a telephone central office, the equipment that connects to subscriber circuits.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">mainframe computer

A large centralized computer system, used for large volumes of data or supporting multiple interactive terminals, with large input/output capacity, generally expected to provide critical services to a business or institution with a predictable degree of reliability.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">mains electricity

Commercial electric power, purchased from an off-site source shared by many consumers. Regional supplies vary in voltage, frequency, and technical standards.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">mains hum

Interference on an audio or visual signal related to the power line frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">marginal stability

Said of a system that neither returns to its initial state when disturbed nor diverges to some unstable condition.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">marine energy

Any technique for extracting useful energy from tides, waves, or salinity or temperature gradients of the ocean.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Marx generator

A kind of circuit for generating very high DC voltage pulses.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Maser

A device that produces microwave energy in a similar manner to a LASER.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">maximum prospective short-circuit current

The calculated value of current that could flow if a short circuit occurred; a parameter for selection of circuit protection devices.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Maxwell's equations

The fundamental relations between electric and magnetic fields, expressed in concise mathematical form.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">mechanical rectifier

An electromechanical device for converting alternating current to direct current, using sets of contacts which operate in synchronism with the AC.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">mechatronics

Combinations of mechanical systems with electronics for sensing and control.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">memristor

A hypothetical non-linear passive two-terminal electrical component relating electric charge and magnetic flux linkage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">mercury-arc rectifier

A mercury-arc valve; a vacuum tube device that converts alternating current to direct current by an arc in mercury vapor; displaced by solid-state devices, but formerly much used especially in high-voltage direct current transmission.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">mercury vapor lamp

A lamp that generates light from a discharge struck in mercury vapor; formerly widely used in outdoor lighting, now replaced by lamps with better efficacy.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">mesh analysis

A strategy for solution of the voltage distribution in some types of electrical networks.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">mesh networking

A topology where infrastructure nodes connect to other nodes such as to convey information.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Metadyne

A DC electric machine with crossed fields and two sets of brushes, used as an amplifier or rotary DC transformer.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">metal rectifier

A rectifier made from copper oxide or selenium; formerly widely used before development of silicon rectifiers.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">micro combined heat and power

Equipment that generates process or space heat and electric power, of a size useful for a single building.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">microcontroller

A microprocessor integrated with memory and input/output circuits, useful for embedded control.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">microelectromechanical systems

An electromechanical system of microscopic size; they may be sensors or actuators.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">microelectronics

That part of the field of electronics dealing with integrated circuits.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">microgeneration

Small-scale electric power production, to provide the needs of a small building or individual consumer.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">microphone

A transducer that changes sound into electrical signals.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">microprocessor

A computer with its logical, arithmetic and control functions implemented on one or a few integrated circuits.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">microstrip

A planar transmission line that is fabricated by printed circuit board technology and is used for microwave-frequency signals.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">microstrip antenna

A planar antenna that is fabricated by printed circuit board technology.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">microwave oven

A heating appliance that uses microwave energy.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">microwave radio

The subset of radio technique using wavelengths that are in the range of 3 GHz or higher.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">microwave

Part of the radio spectrum with wavelengths shorter than 10 centimetres.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Millman's theorem

A theorem stating the relation between branch currents and voltages for multiple sources in parallel.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">mineral-insulated copper-clad cable

Cable with an outer metal cover and insulated by powdered inorganic material, suitable for high temperature; one kind of fire-resistant cable.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">mobile phone

A handset that connects to the public switched telephone network by radio.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Modbus

A brand name for a serial protocol for industrial control equipment communication.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">model predictive control

A control strategy for process systems based on a mathematical model of the process and its disturbances.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">modem

Modulator-Demodulator, an interface between a computer system and a telephone network.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">modulation transformer

Part of a radio transmitter used to impress modulation on one amplifying stage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">modulation

The impression of information on a carrier wave for transmission.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">monolithic microwave integrated circuit

An integrated circuit that operates in microwave frequencies and that can be fabricated by printed circuit board technology.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">monoscope

A raster scan video device that generates a single fixed image for test or identification purposes.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Moore's law

The observation that the number of transistors possible in an integrated circuit doubles approximately every two years.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Morse code

A method of transmitting text by long and short impulses and varying delays between them.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">MOSFET

Metal Oxide Semiconductor Field Effect Transistor, a class of transistor using a single type of charge carrier and with a very thin insulating layer between current channel and control gate. If you count those built into integrated circuits, nearly all transistors are MOSFETs.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">motion control

That part of automation that deals with accurately controlling the movements of machines.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">motor controller

Electrical apparatus that regulates and protects an electric motor, which may be as simple as an on-off switch or a servo system for precision machine tools.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">motor soft starter

A device that reduces the inrush current when an electric motor is first connected to the power supply.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">MP3

A standard for encoding audio in digital form.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">MRI

Magnetic Resonance Imaging, a technique for examining the interiors of, for example, medical patients, using sensitive measurements of the magnetic fields of atomic nuclei.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">multics

An influential early time-sharing computer operating system, first released in 1969.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">multimeter

A test instrument that can measure current, voltage, or resistance (though not concurrently).

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Multisim

A brand of computer software for electronic circuit simulation.

N

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">nameplate capacity

The design power output of a generator, at specified temperature rise.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">nanoinverter

Grid tied inverters rated less than 100 watts, useful for connection of single solar PV panels to a building AC power system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">nanotechnology

Technology that uses devices whose principal dimensions are of the order of a few nanometres.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">National Electrical Code

The United States national technical standard for building wiring installation.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">National Electrical Manufacturers Association (NEMA)

A US trade association for electrical manufacturers that also develops technical standards.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">negative feedback

Feedback from a control system output that tends to oppose the input.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">negative resistance

A voltage/current characteristic where increasing current leads to decreased voltage drop across the device.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">negawatt power

In power grid demand management, that portion of load that can be met by conservation efforts or improved energy efficiency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">neon sign

Strictly, a sign that glows orange because of a discharge through neon gas; less pedantically, any gas discharge tube formed into a sign.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">neon-sign transformer

A high-voltage transformer with features intended to support operation of a neon sign.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">net metering

A metering plan that allows grid customers with their own generation to be billed only for their net import of energy from the grid.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">network analyzer

An analog computer system for modelling power grids; displaced now by digital computers.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">network cable

Cables intended for use in data interconnections, with defined performance parameters.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">network protector

A type of circuit breaker used to isolate a fault from a multi-transformer supply network.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">neural network

An artificial neural network, or one of the biological neural networks that the artificial networks are inspired by.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">nodal analysis

A technique for analysis of currents in an electrical network.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">node

A defined point in an electrical network, with some potential relative to a reference node and where currents can be summed.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">noise cancelling

A type of microphone that preferentially picks up a nearby sound source and rejects ambient noise.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">noise reduction

The techniques used to reduce the perception of noise in a communications path.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">noisy-channel coding theorem

A theorem that establishes the limits of the error-free data transmission in a noisy communication channel

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">nominal impedance

The rated impedance of an element of a circuit.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">nonlinear control

The class of control problems relating to the control of systems that are nonlinear.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">nonode

Any electron device (although practically, only vacuum tubes) with nine internal active electrodes controlling electron flow.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Norton's theorem

A theorem which states that any network of current sources, voltage sources, and resistors can be simplified to an equivalent network with only a current source and shunt admittance; the dual of Thevenin's theorem.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">notch filter

A filter with a narrow reject band, used to block, for example, a pilot tone out of a communications network.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">NTSC

The US National Television Systems Committee, that developed the analog monochrome and color television standards used for more than 60 years for broadcasting.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">nuclear power

Production of electric power (or propulsion power) by nuclear fission or fusion.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">numerical control

Digital automatic control, especially of machine tools.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Nuvistor

A type of miniature vacuum tube, developed around the same time transistors became common in consumer electronics.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Nyquist frequency

The maximum frequency that a sampling system can represent accurately.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Nyquist stability criterion

A graphical technique for evaluating stability of a feedback system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Nyquist–Shannon sampling theorem

A theorem that establishes the necessary rate to accurately sample a band-limited signal.

O

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">observability

In control theory, a measure of how well the internal state of a system corresponds to its measurable outputs.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Oersted

The CGS unit of magnetic field H.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ohm

The SI unit of electrical resistance.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ohmmeter

An instrument that measures electrical resistance.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Ohm's law

The mathematical relationship between voltage, current, and resistance.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">one-line diagram

A simplified schematic diagram of a power system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">on-premises wiring

Telecommunications wiring owned by the customer.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">open-circuit test

A test, of a transformer or other device, with no load connected.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">open-circuit voltage

The voltage developed at the terminals of a device with no load connected.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">open-circuit time constant method

A method for approximately evaluating the transfer function of an electrical network.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">operational amplifier

A type of amplifier with differential inputs, widely used in circuits where feedback determines the circuit properties.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">optical fiber

A glass or plastic fiber used to convey signals transmitted by visible light or infrared radiation.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">optimal control

The branch of control theory studying optimization of a control system to fit some optimization criterion.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">oscillation

A periodic cyclical motion or disturbance.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">oscilloscope

An instrument for graphically displaying a waveform as a function of time.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Oudin coil

An early form of high-voltage induction coil identical in principle to a Tesla coil except for being constructed essentially as an auto-transformer.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">out of phase

The condition when AC generation sources are not synchronized.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">overhead line

Outside plant run on poles or other structures; power transmission or telecommunication wires.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">oversampling

Sampling a signal at a rate higher than required by the Nyquist criterion.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">overshoot

A transient excursion of a signal beyond its stead state value.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">overvoltage

Application of more than rated voltage to a device.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">oxygen-free copper

A grade of copper preferred for electrical applications for its low electrical resistance.

P

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">padmount transformer

A kind of metal enclosed distribution transformer suitable for mounting on grade.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">pantograph

A linkage that supports the current collector of an electric locomotive.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">paraformer

A device similar to a transformer that couples energy between two circuits by varying magnetic parameters.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">parameter estimation

In estimation theory, the practice of assigning values to a process model so it accurately predicts the process's behavior.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Park transform

A mathematical technique useful in the analysis of three-phase systems.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">partial discharge

Breakdown of insulating gas or solid material by an electric field, but without formation of an arc.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">passivity

Incapable of adding energy to a signal or process.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">patch cables

Short cables with connectors, used to make connections between outlets of a patch panel or for temporary connections to a system under test.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">peak demand

The maximum rate at which energy is consumed from an electrical grid; may be either an instantaneous measure or the maximum energy transferred in some interval such as 15 minutes.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Peltier–Seebeck effect

The thermoelectric effect, movement of heat due to electric current flow.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">pentagrid converter

A type of self-oscillating vacuum tube used a frequency mixer in superheterodyne receivers.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">pentode

Any five-electrode electron device, but usually a kind of vacuum tube.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">permanent magnet synchronous generator

An AC generator that uses a permanent field magnet instead of an electromagnet.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">permanent magnet

A magnet that retains its polarization after an external field is removed.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">permeability

The amount of magnetisation in a material resulting from an applied magnetic field.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">phase converter

Any electrical apparatus that converts power from one system of phases to another system, e.g. the conversion of single-phase power to three-phase.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">phase-fired controllers

An AC power controller that adjusts the effective value of output by switching on at a variable time phase in the AC cycle.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">phase locked loop

An oscillator circuit that produces an output signal that is in a fixed timing relation to a reference input.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">phase modulation

Impressing information on a carrier wave by advancing or delaying the waveform slightly; related to frequency modulation.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">phasor

A vector representing a signal of a given frequency in phase space.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">phasor measurement unit

A system that measures the timing and amplitude of voltages and currents on an electrical grid, synchronized over a wide geographic area; the resulting measurements can be used to manage power flow on the grid.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">phonograph

A record player, a device that converts the mechanical movements of a stylus in a disk or cylinder recording groove into sound.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">photocell

A light sensor that produces or alters a voltage when light is present.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">photodetector

Any device that detects visible light.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">photodiode

A two-terminal device whose terminal voltage or current changes in response to light.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">photometer

An instrument that measures light.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">photonics

The technology of conveying information through light or infrared radiation.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">photoresistor

A resistor whose resistance varies when light strikes it.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">phototransistor

A transistor sensitive to light.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">PID controller

A process control system that has proportional, integral and derivative terms in its response to errors between measured value and setpoint.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">piezoelectric effect

Production of a voltage in response to mechanical pressure or mechanical deformation.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">piezoelectric motor

A type of motor that uses piezoelectric elements to generate force.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">PIN diode

A multilayer semiconductor diode with a thin region of intrinsic material between its p-doped and n-doped regions.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">planar graph

In network theory, a set of nodes and interconnecting lines that can be given in one plane without crossing lines.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">plasma

A state of matter where electric charges are free to move.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">plenum cable

A fire-resistant data communications cable that is permitted to be installed in the air handling spaces of a modern building.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">plug-in hybrid

A hybrid electric vehicle that can be recharged from grid power as well as its own engine/generator.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">P-N junction

The boundary between two differently doped regions of a semiconductor.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">polarization density

A measure of the increase of the intensity of an electric field over that in free space, owing to the separation of atomic-scale electric dipoles.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">polyphase coil

A coil intended for connection to a polyphase power supply.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">polyphase system

An alternating current power transmission system using three or more wires, each of which carries a current that is displaced in time with respect to the others.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Pontryagin's minimum principle

A mathematical principle used in the theory of optimal control.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">port

Any place at which energy can be observed to enter or leave a system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">positive feedback

Feedback from the output of a system that tends to increase the effect of any input; if overdone, leads to instability.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">potential difference

A voltage difference, the amount of work required to bring a test charge from one point to another divided by charge magnitude.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">potentiometer

A three-terminal variable resistor, which can be configured as an adjustable voltage divider.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power BJT

A bipolar junction transistor that can be used in circuits handling a watt or more of power.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power cable

A flexible, insulated electrical conduit used to conduct and transmit electric power.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power conditioner

Any system intended to alter some property of the bulk power supply to improve it for some application; such as filters, surge suppressors, voltage regulators, uninterruptible power supplies, and many others.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power consumption

The rate at which a device consumes energy.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power converter

Any apparatus intended to convert electric power from one form to another, e.g. by converting between alternating current (AC) and direct current (DC) with an inverter or rectifier, or by changing frequency or phase number.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power distribution

That portion of an electrical grid between the substation or bulk supply and the end consumer.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power electronics

The class of electronic devices handling power greater than one watt.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power engineering

That part of electrical engineering that deals with the generation, distribution and consumption of electrical power.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power-factor correction

Apparatus intended to bring the power factor of some load closer to 1.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power factor

The ratio of apparent power flowing to a load divided by the real power.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power-flow study

A load flow study; mathematical prediction of the magnitudes and direction of power flow in an existing or planned power grid; an essential part of grid management.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power generation

The practice of converting other energy sources to electric power.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power grid

An interconnected network of generators, transmission lines, and apparatus for reliable and economic transmission and utilization of electric power.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power inverter

See inverter.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power-line communication

The impression of carrier waves on a power line circuit for signalling purposes.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power MOSFET

A metal oxide semiconductor field effect transistor suitable for use in circuits handling more than a watt of power.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power plant

A facility that converts other energy forms into electric power.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power rating

The nominal power that an apparatus or machine can handle, with specified or customary temperature rise and life expectancy.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power quality

Conformance of an electrical power supply with its specifications.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power storage

A facility that changes electric power into some form that can be stored and usefully reconverted back to electric power, for example, pumped storage or battery systems.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power supply

A subsystem of a computer or other electronic device that turns electric power from a wall plug or batteries into a form suitable for use by the system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power-system automation

The implementation of power-operated switching and control that allows automatic operation of power system elements, instead of manual operation.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">power-system protection

The technology of limiting the spread of failures of a power system to a minimum, and of preventing permanent damage to apparatus or conductors by such faults.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">printed circuit board

An etched wiring assembly for interconnection of electronic components.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">printer

A device that makes permanent human readable images and text from computer data.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">process control

The field of study of automatic control of processes.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">programmable logic controller

A computer system designed to be rugged enough for industrial use and with a programming environment highly tuned to the domain of industrial control problems.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">programming language

A formalism for human-readable instructions to a computer.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">protective relay

An electromechanical or electronic device that detects faults on a power system and can signal circuit breakers to operate.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">proximity effect

The increase in circuit resistance when the magnetic fields of multiple AC currents interact.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">pulse transformer

A transformer designed to create or transmit pulses.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">pulse-width modulation

Transmission of information by varying the duration of pulses, or, varying the average output voltage of a power converter by varying the duration of pulses.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">pulse-amplitude modulation (PAM)

Transmission of information by varying the magnitude of a stream of pulses of fixed frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">pulse-code modulation

Any system for conveying analog information by altering some property of a stream of pulses.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">pumped-storage hydroelectricity

A grid energy storage system that pumps water uphill for later use by a hydroelectric generator plant.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">push switch

A device that closes or opens an electrical circuit when pushed.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">push–pull converter

A converter with two sets of primary switching elements so that the transformer primary voltage can be reversed on each cycle.

Q

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">quadrature booster

A phase shifting transformer that can inject voltages that are time delayed with respect to the input voltage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">quality factor

In a resonant circuit, the ratio of stored energy to energy dissipated on each cycle of oscillation.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">quantization

Analog to digital conversion, changing a continuously varying analog signal to discrete digital numbers.

R

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">radar cross section

The effective reflecting area of a radar target, which varies with frequency, geometry, and surface composition.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">radar

Radio Detection and Ranging, the techniques for observing the speed and position of objects by reflected radio waves.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">radio frequency

Electromagnetic waves with frequencies less than that of infrared radiation; commercially important radio frequencies range from tens of kilohertz up to around a terahertz.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">radio transmitter

Apparatus designed to generate radio frequency electric current, which, connected to an antenna, can radiate energy through space.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">radio

The technology of radio frequency devices.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">railway electrification system

A set of standardized methods for applying electric power in railway traction.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Rankine cycle

A thermodynamic cycle, an idealized version of the operation cycle of a steam turbine.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">reactive power

That component of apparent power flow due to the return to the source of energy stored in a load's electric or magnetic fields, that does no useful work at the load.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">real-time operating system

A computer operating system that ensures responses with a bounded time to events such as in a controlled process.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">receiver

The apparatus that takes radio-frequency currents induced in an antenna and turns them into useful signals.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">rechargeable battery

A secondary battery; a battery that can have a useful portion of its capacity restored by connection to a supply of electric current.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">reciprocity (electrical networks)

A theorem that states that the current injected into one point in a network will produce a voltage at a second point that is identical to the voltage produced at the first point by injection of the same current at the first point

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">reciprocity (electromagnetism)

An observation that electric currents and electric fields can be analyzed from either point of view as regards the source of the energy in the system; for example, in radio, a good transmitting antenna is generally also a good receiving antenna.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">record player

A phonograph; a device that turns the variations in a disk or cylinder recording groove into sound.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">rectifier

A device that converts alternating current (which periodically reverses) to direct current that flows in only one direction; may be a solid-state, vacuum tube or electromechanical device.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">rectiformer

A combination of a transformer and a rectifier, used in electrochemical processes or supply of electrostatic precipitators.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">recursive least squares filter

An algorithm for a digital filter system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Reed switch

An electrical switch made of two thin strips of ferromagnetic metal, which touch when subject to a magnetic field.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">regenerative braking

A braking scheme that returns energy to the source.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">regenerative circuit

A circuit that employs positive feedback; can be an amplifier or an oscillator.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">relaxation oscillator

An oscillator that relies on an active device periodically changing state; such oscillators usually produce a square-wave or sawtooth waveform, different from the approximately sinusoidal waveshape of a harmonic oscillator.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">relay

An electrically operated switch.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">reluctance motor

A type of electric motor that induces non-permanent magnetic poles on the ferromagnetic rotor, relying on varying magnetic reluctance; the rotor carries no windings.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">remanence

That portion of the applied magnetic field that the material retains when the external field is removed.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">remote racking system

A system for inserting circuit breakers into switchgear that allows the operator to stay at a safe distance from any possible arc hazard.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">remote sensing

Acquisition of measurements of an object without contact, for example, measuring soil moisture by radar from an aircraft.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">renewable electricity

Electric power derived from primary energy sources that replenish on a rapid scale or that are not appreciably diminished by human exploitation.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">renewable energy payments

Any incentive program to improve the economic return of a renewable energy project.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">renewable energy policy

Government plans to displace fossil fuels with renewable sources.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">repeating coil

An old name for a transformer, especially one used in telephone circuits.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">repowering

Refurbishing the equipment of a power plant, with a view to improved efficiency or life span.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">repulsion motor

A wound rotor induction motor using a pair of short-circuited brushes on a commutator.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">resettable fuse

A circuit protective device that opens on excess current, and then, on cooling off, restores the circuit automatically.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">residual-current device (RCD)Lua error: Internal error: The interpreter has terminated with signal "24".

Lua error: Internal error: The interpreter has terminated with signal "24".

A type of Earth-leakage circuit breaker designed to interrupt an electrical circuit when the currents passing through line and neutral conductors are not equal, which indicates that some amount of current is leaking to ground or to another unintended path that is not part of the circuit. By detecting this imbalance of phase currents and automatically interrupting the circuit, these devices function as protective systems to reduce the severity of injury caused by an electric shock.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">resistive circuit

A circuit containing resistive elements only, no capacitors or inductors.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">resistivity

The property of a material that impedes current flow.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">resistor

A circuit component that primarily has resistance.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">resolver

A transformer-like rotary transducer that measures rotation as an analog value.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">resonant cavity

An opening that when excited by an electron stream or other means, oscillates at a particular frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">resonant inductive coupling

A form of energy transfer between two physically close tuned circuits.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">return loss

A measure of the power loss due to a signal reflection by a discontinuity in a transmission line or an optical fiber.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">RF connector

An electrical fitting used to connect cables carrying radio frequency currents.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">RF engineering

The profession that deals with application of radio frequency energy to useful ends.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">rheoscope

Obsolete name for an ammeter; now an instrument for measuring fluid viscosity.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">rheostat

Obsolete name for a two terminal variable resistor, usually with a rotating shaft to allow manual or motor driven adjustment.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">right-hand rule

A mnemonic device for remembering the definitions of the directions of current and magnetic field in generators.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ripple

A periodic variation in the amplitude of a DC signal, such as can be found in a power supply with partly effective filtering.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">RLC circuit

A circuit that has only resistors, inductors, and capacitors in it.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">robotics

The field of automation that deals with manipulators, especially those that mimic human appendages.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">robust control

A static control algorithm that can produce acceptable performance over an anticipated useful range of process disturbances.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Rogowski coil

A current sensing coil that produces a voltage proportional to the rate of change of current; by integration, this can be turned into a measure of current.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">root locus

A graphical method for analyzing the properties of a transfer function as some parameter is varied.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">root mean square

The root mean square value of a waveform is the DC value that corresponds to equivalent heating value.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">rotary converter

An electric machine that converts electric power between two forms, say, AC and DC or single-phase and three phase, or between two different frequencies of AC (the latter two can be performed by the same machine).

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">rotary encoder

A transducer that converts rotation of a shaft to a measurement.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">rotary switch

A switch operated manually or electrically with a rotary motion of the contacts.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">rotary transformer

A transformer used to couple electric signals or power between rotating parts.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">rotary variable differential transformer

A transformer-like transducer that measures rotation as an analog value.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">rotor

That part of an electrical machine that rotates. Not necessarily the armature.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Routh–Hurwitz stability criterion

A criterion for predicting the stability of a system with a given transfer function.

S

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Sallen–Key filter

A family of active filters with a second-order characteristic, first described in 1955.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">sample and hold

A circuit that takes a sample of a changing analog value and holds onto it until the value can be processed by some other stage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">sampling

The process of taking a continually varying signal and turning it into a stream of numbers taken at regular intervals.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">sampling frequency

The rate at which an analog value is sampled.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">satellite

A natural or artificial object that circles another, bound only by gravity.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">satellite radio

A radio broadcasting service using signals from an Earth satellite to customer receivers.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">saturation

That point in the magnetization of a substance where most magnetic domains are aligned with the external field; further increase of the magnetizing force (H) gives only small increase in the magnetization (B).

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">SCADA

Supervisory Control and Data Acquisition, management of geographically distributed automation systems such as for an electrical grid.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">scattering parameters

A matrix that describes the electrical behavior of linear electrical networks, most prominently the distributed microwave systems.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Schmitt trigger

A circuit that behaves like a snap-action switch, suddenly changing state as an analog signal increases; displays hysteresis.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Schottky diode

A diode that relies on the junction between a semiconductor and a metal.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Scott-T transformer

A transformer connection for balanced interconnection of a two-phase system and a three-phase system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">s-domain

A Laplace transform converts a function from the time domain to the "complex frequency" s-domain; making certain mathematical operations much simpler to evaluate.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">SDTV

"Standard definition television" – what descriptions of HDTV call any system with 625 scan lines or less.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">segmentation

A step in digital image processing that groups picture elements of an image that notionally represent some physically significant property of the imaged objects.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">selenium rectifiers

One type of metal rectifier, though selenium is considered a "metalloid" – formerly much used but now replaced by silicon semiconductors.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">semiconductor

A substance with electrical conductivity between that of insulators and conductors; displays a negative temperature coefficient of resistance, and is also sensitive to light. The conductivity of semiconductors can readily be altered by trace amounts of other substances, leading to devices that are the foundation of nearly all modern electronics.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">semiconductor device

A device that relies on substances with electrical conductivity between that of insulators and conductors; the controllable conductivity of these materials makes most of modern electronics possible.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">semiconductor fabrication

The process of turning the raw source of silicon into transistors and integrated circuits.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">sensor

A device or system that converts some physical event into an electronic signal, for further use in measurement or control.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">serial communication

Transmission of data as a single series of bits over a communication path.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">series and parallel circuits

Electrical circuits where current passes through multiple elements either one after the other, or side by side, like the rungs of a ladder, or both.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">shaded-pole motor

An alternating current single-phase motor that produces a rotating magnetic field by a turn of wire around part of a field pole.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">shaft voltage

An objectionable stray voltage that appears on the rotating part of an electrical machine; very deleterious to supporting bearings.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">shielded twisted pair

Two wires, wrapped around each other and covered with a flexible shield conductor; intended to reject external interference.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">short-circuit test

A test of machines or apparatus where the load terminals are directly connected; usually done at reduced power to prevent damage, but destructive short circuit testing may be carried out on circuit protective devices.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">short circuit

A path in a circuit that has negligible resistance; often un-intended, a fault.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">shunt

A small value resistor connected around a metering element to carry most of the current; only a small part passes through the meter.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">siemens

A reciprocal ohm, the SI unit of conductance. The former Siemens mercury unit was a unit of resistance.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">signal

Some intentional modification of a physical communication path that is intended to convey information from one place to another.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">signal processing

The technology to extract information from signals.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">signal strength

A measure of the usable power of a physical signal.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">signal-flow graph

A formal mathematical treatment of the representation of signal flow through a system, such as an analog computer or a radio receiver.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">signal-to-noise ratio

A measure of the power contained in the useful part of the signal, to the power contained in noise. Often measured in decibels; for example, in sound reproduction a 40 or 50 decibel signal to noise ratio would be broadcast quality, whereas a 10 decibel ratio would represent very difficult operating conditions for a voice radio system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">silicon controlled rectifier

A four layer semiconductor switching device that can stand off an applied voltage until triggered by an electrical pulse on a control lead.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Silicon Valley

Initially, a region of California known for a large number of electronics technology firms.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">sine wave

The waveform of the mathematical sine function; a fundamental wave shape, free of harmonics.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">single-phase electric power

An alternating current power system using only two wires, where peak voltages in each wire occur at the same time.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">single-sideband modulation

A radio carrier modulation system where redundant frequencies of one duplicate side band are filtered out along with the carrier, to save transmitter power.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">skin effect

The tendency of alternating current to flow at the periphery of a conductor; significant for large conductors at power frequencies, and increasingly significant as the frequency increases.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">sliding mode control

A control strategy for a nonlinear system that uses discontinuous control signals.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">slip ring

A sliding continuous electrical contact between a machine's rotating parts and the fixed external circuit.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">small-signal model

An analytical tool for systems that show significant non-linearity for large signal excursions.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">smart grid

The application of information technology to improve performance of the electrical grid.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Smith chart

A graphical tool for display of the impedance of devices at varying frequencies, and for solution of problems of impedance matching in radio frequency design.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">software engineering

The profession of designing software systems to meet specified performance requirements.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">software

The set of instructions and data that direct a computer system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">solar cell

A photovoltaic cell, used to produce power from sunlight.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">solar energy

Useful energy extracted by some means from sunlight.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">solar micro-inverter

An inverter suitable for use with a single solar panel.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">soldering

The process of joining metals using a low melting point filler metal; a critical process in the assembly of most electronic devices.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">solenoid

A coil of wire used to create a magnetic field; often a device with a ferromagnetic plunger that moves when the coil is energized.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">solid state

Electronics that relies on current flow through crystalline lattices.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">solid state physics

That branch of physics that studies arrangements of atoms in fixed arrays.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">sound recording

The technology of recording sound for later reproduction.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">space vector modulation

A control strategy for variable frequency motor drives.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">spark spread

The difference between the revenue from selling a unit of electricity and the cost of the fuel used to make it.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">spark-gap transmitter

A former type of radio transmitter that generated radio frequency current by exciting resonance of a tuned system with an electric spark, used almost entirely for transmission of Morse code.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">spectrum analyzer

An instrument that graphically displays the amplitude of signals in a narrow bandwidth across a frequency band.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">speech processing

The techniques for improving the intelligibility of human speech in a communications system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">SPICE

A set of computer programs for modelling the behavior of electronic circuits.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">split phase distribution

A type of distribution system that uses a center tapped transformer to provide two voltages to a building wiring system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">split phase motor

A type of single phase motor that uses a resistor, inductor, or capacitor and two windings to obtain a rotating magnetic field.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">square wave

A waveform that spends equal times at the positive and negative peak values with rapid transitions between them.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">stability theory

The systematic study of control systems that deals with their response to disturbances.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">stable polynomial

That class of polynomials representing the transfer functions of stable control systems.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">stacking factor

A measure of the efficiency of filling the space of a machine core or winding; the proportion of active material in any given unit cross section.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">standing wave ratio

A measure of impedance mismatch for transmission lines in microwave engineering; the ratio of peak amplitude of a standing wave to its minimum.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">star-mesh transform

A mathematical technique used in circuit analysis.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">state observer

In control theory, that which discovers and reports the internal state of a controlled system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">state space representation

A mathematical technique to represent the internal state of a controlled system as a vector in a Euclidean space.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">static VAR compensator

A system that adjusts reactive power flow without moving parts, such as an electronically controlled capacitor bank.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">stator

That part of a rotating electrical machine that remains stationary.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">steady-state

The condition of a control system where changes due to some disturbance are no longer occurring at a significant rate.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">steam turbine

A rotating machine that converts the energy of expanding steam to mechanical power through its interactions with sets of moving and stationary blades.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">step response

The behavior of a control system in response to an abrupt change of input.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">stepper motor

An electric motor that moves its shafts in discrete steps as different poles are energized.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">stereophonic sound

Sound reproduction systems intended to reproduce sound emanating from more than one direction.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Stokes' theorem

A theorem about integration of three-dimensional functions, much used in analysis of electric fields.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">storage tube

A type of cathode ray tube, used for storing images or data.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">stray capacitance

A property of every conductor, when considered as a non-ideality.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">structured cabling

A system for design of the telephone and data communications cable systems of a building.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">submarine communications cable

A telephone or telegraph cable that is substantially under water.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">sulfur hexafluoride circuit breaker

A kind of automatic circuit protection switch that breaks current in an atmosphere of pressurized sulfur hexafluoride gas to extinguish the arc.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">super grid

A wide area power transmission network that allows interchange over continental distances.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">supercomputer

A computer with a substantially higher level of performance than a general-purpose machine; especially adapted for high intensity calculation on large data sets.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">superconducting electric machine

An experimental type of generator or motor that has part of its electric circuits in the superconducting state.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">superconductivity

The loss of all electrical resistance at inconveniently low temperatures.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">superheterodyne receiver

A radio receiver that changes incoming frequencies to a fixed intermediate frequency for processing.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">superposition theorem

The useful property of a system where the response to the sum is the sum of the responses.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">surge arrester

A device intended to absorb brief transient overvoltages to protect machines or apparatus.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">surge protection

The measures taken to protect machines and apparatus from transient overvoltages.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">switch

An electrical device that opens and closes a circuit; it may be manually operated, automatically operated by some other electrical circuit, or operated by the change in some physical condition such as flow, level, or temperature.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">switched reluctance motor

A motor that relies on induced magnetism in salient poles, instead of a rotor winding.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">switched-mode power supply

A power converter that regulates voltage by adjusting the time duration of a switching device; this gives reduced heat dissipation compared to an equivalent linear regulator device.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">switchgear

An array of switches, circuit breakers and related apparatus for power distribution.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">symbolic circuit analysis

Analytical circuit analysis in terms of expressions with variables, instead of numerical solutions for a particular case of values.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">symmetrical components

A technique to simplify analysis of unbalanced polyphase systems.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">synchro

A synchromotor, a class of electrical motors that follows the rotation of a source.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">synchronization

Aligning the timing of two or more sources, such as synchronizing a generator before connecting it to a grid.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">synchronous circuit

A logic circuit where internal state changes only propagate in step with a master clock signal.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">synchronous motor

A motor that rotates at a speed exactly related to the supply frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">synchronous rectification

A converter from alternating to direct current, where switching devices actively are operated in step with the positive and negative excursions of the supply.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">synchroscope

An instrument used to bring an alternating current generator into synchronization with a grid, that uses a moving pointer or set of lamps.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">system identification

The technique of development of a mathematical model of a controlled system; model identification.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">system on a chip

An integrated circuit that combines multiple significant subsystems of a product on one die, for example, analog signal processing and digital controls.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">system on module

A packaging of significant functions of a complete product in a form that can be used in more than one product.

T

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">tachometer

An instrument that measures rotational speed (or angular velocity).

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">tap

A connection to a winding at some point between the ends, used to adjust voltage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">tap changer

A switch that selects which transformer tap is connected to an external circuit; may be manually operated, or power operated; some types can be operated under load for voltage regulation purposes.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">technical drawing

Drawings intended to convey information for construction, operation or maintenance of a system or equipment.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">telecommunication

The field that deals with transmission of information over distances longer than can be covered by an unaided human.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Telecommunications Industry Association

A US based trade association that develops technical standards.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">telegraph

A system for transmitting text messages, by wire or other means.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">telegrapher's equations

Coupled linear partial differential equations that relate the voltage and current on a transmission line.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">telephone balance unit

A balun, a transformer used to convert between balanced and unbalanced lines, as used in telephone circuits.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">telephone line

Outside plant that connects a central office to subscriber equipment.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">telephone

Transmission of voice by electrical means.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">television

Transmission of moving images by electrical means.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Tellegen's theorem

A theorem relating to branch currents in an electrical network.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">tesla

The SI unit of magnetic flux density.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Tesla coil

A kind of resonant transformer capable of very high voltages; almost identical to an Oudin coil except that it has separately wound primary and secondary.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">tetrode

An electron device, nearly always a vacuum tube, with four internal active electrodes.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">thermionic emission

Emission of electrons from a hot surface; the Edison Effect was an early instance of description of this phenomenon.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">thermistor

A temperature sensitive resistor with a large, somewhat variable, temperature coefficient of resistance.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">thermocouple

A junction of two dissimilar metals that generates voltage when at a temperature above absolute zero.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">thermoelectric effect

The conversion between heat flow and current flow, and the reverse.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">thermostat

A temperature sensing switch.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Thévenin theorem

A theorem which states that any network of current sources, voltage sources and resistors can be simplified to an equivalent network with only a voltage source and series impedance; the dual of Norton's Theorem.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">third rail

An energized conductor in the track bed, using a sliding contact to transfer power to an electric train.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">three-phase AC railway electrification

Application of three-phase power to railways.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">three-phase electric power

Electric power transmission using three conductors carrying currents which peak at separate evenly spaced times in each cycle; widely used for motors.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">thyristor

A four layer semiconductor device that stands off applied voltage until triggered.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">thyristor drive

A variable speed drive, usually with direct current motors, using thyristors as the switching elements.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">tidal power

Extraction of useful energy, usually as electric power, from the tidal rise and fall of water.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">time sharing

A system whereby multiple human users of a computer can proceed as if they had sole use, while the computer processes each user's software in round-robin fashion.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">time-invariant system

A systems whose characteristics don't vary significantly with time.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">topology

The shape of an electrical network, independent of its size or values.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">toroidal inductors and transformers

Magnetic coils wound around a ring of ferromagnetic material.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">total harmonic distortion (THD)

A measure of the magnitude of harmonically-related frequency components a signal processing stage adds.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">traction battery

A battery used to store energy for propelling a wheeled electric vehicle.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">traction current

Power supply for wheeled electric vehicles.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">traction motor

An electric motor for a wheeled vehicle.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">traction substation

A substation that supplies current to a railway, subway or similar electric wheeled transit.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transatlantic communications cable

A cable for voice or data running under the Atlantic Ocean.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transceiver

Apparatus that combines a receiver and transmitter.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transconductance

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transducer

An instrument that converts a physical quantity into another electrical or physical quantity.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transfer function

The mathematical relation between input and output, usually expressed in terms of frequency or complex frequency (s-domain).

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transformer oil testing

Examination of transformer oil for its insulating strength, dissolved moisture and other properties, to ensure it is still suitable for use.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transformer oil

A hydrocarbon liquid that cools and insulates transformers and other types of electrical apparatus.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transformer

A static arrangement of conductors and possibly magnetic materials, that transfers energy by electromagnetic induction.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transformerboard

A kind of insulating paperboard used for internal structures of large oil filled power transformers.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transient response

The short-time response of a system to a disturbance.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Transil

A brand of transient voltage suppression diode.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transistor

A three terminal solid state device used as an amplifier or switch.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transmission

The process of getting a signal from one point to another.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transmission line

An arrangement of conductors for movement of electric power; used from DC to upper radio frequencies.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transmission system operator

A corporation that runs the transmission system between sources of power and distribution substations.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transmission tower

A structure for support of overhead transmission wires.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">transmitter

Apparatus that prepares a signal for emission into some medium, such as a radio transmitter or a sonar transmitter.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">traveling-wave tube

A type of microwave amplifier vacuum tube.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">trembler coil

A kind of high-voltage coil that includes an interrupting mechanism, formerly used in automobile ignition systems.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">TRIAC

A variation of the thyristor that can pass bidirectional (ac) current.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">triangle wave

A waveform composed of straight-line segments that extend from minus peak to plus peak.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">trigger transformer

A transformer that generates a pulse to initiate some other device, such as a thyristor or a flash tube.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">triode

An electron device, nearly always a vacuum tube, that has three active electrodes.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">trolley pole

A support for a current collector on a vehicle.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">trolleybus

Strictly, a passenger vehicle that collects motive electric power from a pair of overhead conductors.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">tuned circuit

A circuit that displays a peak response at some frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">twisted pair

Two wires twisted around each other, possibly covered with an overall sheath; this configuration rejects some kinds of interference.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">two-phase electric power

An electric power system using two sets of alternating currents, displaced in time by a quarter period.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">two-port network

A network that has two places to exchange energy with its surroundings.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">two-sided Laplace transform

A variant of the Laplace transform that simplifies certain operations.

U

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ubiquitous computing

A scenario where computer science is made to appear everywhere.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ultrasonic motor

A motor that relies on a component oscillating at an ultrasonic frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ultrasonics

Term for the field of study pertaining to pressure oscillations in air or other media that are above the range of human hearing.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">ultrasound

Sound having a frequency above the range of normal human hearing. A portmanteau of the former description of 'ultrasonic sound'

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">undersampling

Sampling a signal at less than the Nyquist rate; can produce alias frequencies or other artifacts.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">unijunction transistor

A three terminal semiconductor device with a definite switching characteristic and only one PN junction.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">unshielded twisted pair

Two wires wrapped around each other, but without a conductive cover.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">upsampling

Sampling at greater than the Nyquist rate, which makes filter design easier.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">utility frequency

60 or 50 cycles per second, used for electric power.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">utility pole

A columnar structure that carries wires for electrical power distribution, cable television, telephone or similar services.

V

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">vacuum capacitor

A capacitor using vacuum as its dielectric; useful at high voltages or radio frequency.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">vacuum tube

An electron device that relies on flow of electrons through a vacuum or low-pressure gas; a valve. The first electronic devices that could amplify.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">valve

A switching element (mercury arc, thyristor, or other device) in a high-voltage direct current converter; each phase contains two or more valves, which may be series-connected for higher voltages. Or, a vacuum tube.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">variable capacitor

A capacitor whose value can be changed, by rotating a shaft, squeezing a plate or by an electrical signal; for example, as used to tune a radio.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">variable-frequency drive

A power converter that varies the speed of an AC motor by changing its frequency; usually, today, a solid-state device.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Variac

One brand of adjustable transformer, that can essentially continuously vary the ratio between primary and secondary.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">varicap

Variable capacitor – usually a diode whose reverse-biased junction capacitance can be varied by applied voltage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">varistor

Variable resistor – a protective device that has a high resistance at low voltage but momentarily switches to lower resistance on exposure to a high voltage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">vector control

A strategy for control of variable-speed motor drives.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">vector group

The classification of the connections of a polyphase transformer.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">vehicle-to-grid

A concept to use electric vehicle batteries as a form of grid energy storage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">vehicular automation

Automatic systems to assist, or replace, the driver of a vehicle.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Versorium

An antique version of an electroscope.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">vibrator

An electromechanical interrupter, part of a DC-to-AC converter in a battery-operated vacuum tube radio, or similar application. Some had additional contacts to act as a synchronous rectifier.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">video camera tube

A family of vacuum tube devices used to pick up images and transmit them electronically.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">video processing

The techniques used to enhance video images.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">virtual instrumentation

A software-intensive measuring system that can be programmed to emulate any of a number of conventional measuring instruments, or some combination of measuring functions.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">virtual power plant

A strategy for managing a collection of disparate power sources, interconnected with a communications network, as if they were a single centralized power plant.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">VLSI

Very Large Scale Integration, the ability to put hundreds of thousands of interconnected transistors onto one chip.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">volt

The SI unit of electrical potential difference; moving a charge of one coulomb through a potential of one volt transfers one joule of energy.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltage

The electric potential difference between two points.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltage compensation

Generally, adjustment of a voltage source to compensate for voltage drop; techniques differ widely between a computer power supply and a long-distance power line.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltage-controlled amplifier

An amplifier that has its gain controlled by a voltage signal.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltage controller

A device that adjusts the (effective) voltage to a load.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltage converter

Any device that changes electric power at one voltage to power at a second; a transformer is a common example of an AC voltage converter.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltage division

A circuit that produces an output voltage that is some, perhaps adjustable, fraction of the input voltage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltage doubler

A rectifier circuit that can product an output DC voltage of nearly twice the input AC voltage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltage regulation

A measure of how a source maintains its output voltage for varying load.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltage regulator

A system that automatically stabilizes the voltage at which power is supplied to a downstream system.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltage source

In circuit theory, a hypothetical element that maintains a specified voltage between its terminals independent of the current through it.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltage spike

A transient electrical voltage higher than normal appearing on an electrical supply.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltage-to-current converter

A circuit that produces an output current proportional to an input voltage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">volt-ampere

The unit of apparent power in an AC circuit.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">voltmeter

An instrument for measuring potential difference.

W

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">war of the currents

The late 19th century commercial dispute on whether AC or DC was the best system for power distribution.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Ward Leonard control

A speed control system for DC machines using an interconnected generator and motor.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">watt

The SI unit of power, work done per unit time.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">wattmeter

An instrument that measures electrical power.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">waveguide

A tubular structure that guides electromagnetic waves, much used at microwave frequencies; an optical fiber is a kind of optical waveguide.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">weber

The SI unit of magnetic flux.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">wet transformer

In telephone systems, a matching transformer that can operate while carrying a substantial DC "wetting" current.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Wien bridge oscillator

A type of electronic oscillator that generates sine waves and is based on a bridge circuit.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Wiener filter

A class of filters used in signal processing, used to fit an estimate to noisy signal data.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Williams tube

A cathode ray vacuum tube used as an early form of computer memory.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">wind farm

An array of two or more wind turbines, usually sharing a substation.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">wind power

Generation of electricity (sometimes mechanical power) from wind.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">wind turbine

A rotating machine that extracts energy from wind.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">wire

A strand of metal much, much, longer than it is wide; a conductor, often coated with insulation.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">wireless network

Data network relying on radio for the connection to end device; may span a building or a larger area.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">wireless telegraphy

Transmission of text by radio; usually implies Morse or radio-teletype.

X

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">X-ray

Electromagnetic radiation with wavelengths shorter than ten nanometres. Strictly: radiation that is produced in the electron shell of atoms.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">X-ray lithography

A developing technique for production of very high density structures in integrated circuits.

Y

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Yagi antenna

A type of radio antenna using a feeder element, one or more parasitic reflector elements, and one or more director parasitic elements to provide a directional characteristic; the classic home TV rooftop antenna was usually a Yagi antenna.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Y-delta transform

A mathematical technique in circuit analysis to simplify a circuit.

Z

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Zener diode

Nickname for "voltage regulator diodes" which may rely either on the Zener effect or avalanche breakdown to maintain a roughly constant voltage; the two effects have opposite temperature coefficients of voltage.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Ziegler-Nichols tuning method

It is a heuristic method of tuning a PID controller.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">zigzag transformer

A multiwinding three phase transformer, sometimes used for grounding.

<dt class="glossary " id="Lua error: Internal error: The interpreter has terminated with signal "24"." style="margin-top: 0.4em;">Z-transform

A mathematical operation that converts a set of evenly spaced measurements of an analog signal into a series of frequency components.

References

↑ International Bureau of Weights and Measures (2006), The International System of Units (SI) (8th ed.), p. 120, ISBN 92-822-2213-6, http://www.bipm.org/utils/common/pdf/si_brochure_8_en.pdf
↑ American Heritage Dictionary of the English Language, Online Edition (2009). Houghton Mifflin Co., hosted by Yahoo! Education.
↑ The American Heritage Dictionary, Second College Edition (1985). Boston: Houghton Mifflin Co., p. 691.
↑ McGraw-Hill Dictionary of Physics, Fifth Edition (1997). McGraw-Hill, Inc., p. 224.

Lua error: Internal error: The interpreter has terminated with signal "24".

Lua error: Internal error: The interpreter has terminated with signal "24". Lua error: Internal error: The interpreter has terminated with signal "24".

Lua error: Internal error: The interpreter has terminated with signal "24".

[1] International Bureau of Weights and Measures (2006), The International System of Units (SI) (8th ed.), p. 120, ISBN 92-822-2213-6, http://www.bipm.org/utils/common/pdf/si_brochure_8_en.pdf

[2] American Heritage Dictionary of the English Language, Online Edition (2009). Houghton Mifflin Co., hosted by Yahoo! Education.

[3] The American Heritage Dictionary, Second College Edition (1985). Boston: Houghton Mifflin Co., p. 691.

[4] McGraw-Hill Dictionary of Physics, Fifth Edition (1997). McGraw-Hill, Inc., p. 224.

[1]

[2]

[3]

[4]

Glossary of electrical and electronics engineering

Topic: Engineering

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

See also

References