Transducer

A transducer is a device that converts one form of energy into another, usually for the purpose of measuring or exchanging information. There are several varieties of transducers:

* Photoelectric transducers convert electrical energy to light, or vice versa.
* Ultrasonic transducers convert mechanical waves (sound) into electrical signals.
* Antennas convert radio waves to electrical signals.
* Electrochemical transducers convert chemical composition information to electrical signals.
* Pressure transducers convert a pressure reading to an electrical signal.