Nightlight

Short description: Small light fixture used to provide dim illumination during the night

An LED nightlight

A nightlight is a small light fixture, usually electrical, placed for comfort or convenience in dark areas or areas that may become dark at certain times, such as at night or during an emergency. Small long-burning candles serving a similar function are referred to as "tealights".

## Contents

* 1 Uses and cultures
* 2 Light source and variants
* 3 Safety hazard
* 4 Potential health issues and benefits
* 5 References
* 6 External links

## Uses and cultures

People usually use nightlights for the sense of security which having a light on provides, or to relieve fear of the dark, especially in young children. Nightlights are also useful to the general public by revealing the general layout of a room without requiring a major light to be switched on, for avoiding tripping over stairs, obstacles, or pets, or to mark an emergency exit. Exit signs often use tritium radioluminescence. Homeowners usually place nightlights in bathrooms, kitchens and hallways to avoid turning on the main light fixture, especially late at night, and causing their eyes to adjust to the brighter light.[1]

Some frequent travelers carry small nightlights for temporary installation in their guestroom and bathroom, to avoid tripping or falls in an unfamiliar nighttime environment. Gerontologists have recommended use of nightlights to help prevent falls, which can often be life-threatening to the elderly.[2]

The low cost of nightlights has enabled a proliferation of different decorative designs, some featuring superheros and fantastical designs, while others feature the basic simplicity of a small luminous disc.

The 1990 song "Birdhouse in Your Soul" by They Might Be Giants is a song sung from the perspective of a nightlight.[3]

## Light source and variants

Electroluminescent nightlights use little electrical power

Early electrical nightlights used small incandescent lamps or small neon lamps to provide light, and were much safer than small candles using an open flame. The neon versions consumed very little energy and had a long life, but had a tendency to flicker on and off (reminiscent of a candle), which some users liked and others found annoying. In the 1960s, small nightlights appeared that featured a low-power electroluminescent panel emitting soft green or blue light; similar lights are still available today.[4]

Some nightlights include a photocell, which enables them to switch off when the ambient light is sufficiently bright. Other designs also feature a built-in passive infrared sensor to detect motion, and only switch on when somebody is passing by in the dark. With the availability of low-cost LEDs, many different variants have become available, featuring different colours, sometimes changing automatically or in a user-controllable way.

## Safety hazard

The US Consumer Product Safety Commission, or UCPSC, reports it receives about 10 reports per year where nightlights close to flammable materials were cited as responsible for fires; they recommend the use of nightlights with LED bulbs cooler than the four or seven watt incandescent light bulbs still used in some older products.[5]

## Potential health issues and benefits

A University of Pennsylvania study indicated that sleeping with the light on or with a nightlight was associated with a greater incidence of nearsightedness in children.[6] However, a later study at Ohio State University contradicted the earlier conclusion.[7] Both studies were published in the journal Nature.

Another study has indicated that sleeping with the light on may protect the eyes of diabetics from retinopathy, a condition that can lead to blindness.[8] However, the initial study is still inconclusive.

The optimal sleeping light condition is said by some to be total darkness.[9] If a nightlight is used within a sleeping area, it is recommended to choose a dim reddish or amber light to minimize disruptive effects on sleep cycles.[10][1] In addition, nightlights may be useful in locations other than sleeping areas, such as hallways, bathrooms, or kitchens, to allow late night trips to be made without turning on the full light, while preserving a dark sleeping environment.[2]

## References

1. ↑ 1.0 1.1 "National Sleep Foundation". National Sleep Foundation. http://sleepfoundation.org/bedroom/see.php.
2. ↑ 2.0 2.1 McMurdo, M E; Gaskell, A (1991). "Dark adaptation and falls in the elderly". Gerontology 37 (4): 221–4. doi:10.1159/000213264. PMID 1916313.
3. ↑ Reed, S. Alexander; Sandifer, Elizabeth (February 13, 2014). "Blue Canary in the Outlet by the Light Switch, Who Watches Over You?". https://slate.com/culture/2014/02/a-history-of-the-they-might-be-giants-song-birdhouse-in-your-soul.html.
4. ↑ "Electroluminescent Lamps - How They Work & History". http://www.edisontechcenter.org/electroluminescent.html.
5. ↑ "Fire Hazard with Nightlights". CPSC Document #5063. US Consumer Product Safety Commission. http://www.cpsc.gov/cpscpub/pubs/5063.html.
6. ↑ "Is Nearsightedness in Children Linked to Night Light Exposure During Sleep Before Age Two?". Science NetLinks. American Association for the Advancement of Science. http://www.sciencenetlinks.com/pdfs/nearsight_actsheet.pdf.
7. ↑ "Night Lights Don't Lead To Nearsightedness, Study Suggests". Science Daily. March 9, 2000. https://www.sciencedaily.com/releases/2000/03/000309074442.htm.
8. ↑ "Light at Night Protects Diabetics' Eyes". WebMD. June 27, 2002. http://www.webmd.com/content/article/48/39153.htm.
9. ↑ Rettner, Rachel (17 November 2010). "Avoiding Depression: Sleeping in Dark Room May Help". http://www.livescience.com/9004-avoiding-depression-sleeping-dark-room.html.
10. ↑ Hyman, Mark (8 November 2013). "How a Light Bulb Can Help You Sleep Better". The Huffington Post. http://www.huffingtonpost.com/dr-mark-hyman/light-sleep_b_4239765.html.

## External links

* v
* t
* e

* Lamps
* Lighting
* List of light sources

Concepts|

* Accent lighting
* Color temperature
* Efficiency
* Glare
* Lamp
* Light fixture
* Light pollution
* Lightbulb socket
* Task lighting

Methods of generation|

| Incandescent|

* Regular
* Halogen
* Nernst

|

Luminescent|

* Fluorescent
* Fluorescent lamp (compact)
* Fluorescent induction
* Photoluminescent
* laser lamp
* Chemiluminescent
* Solid-state
* LED bulb
* Cathodoluminescent
* Electron-stimulated
* Electroluminescent
* field-induced polymer

Combustion|

* Acetylene/Carbide
* Argand
* Campfire
* Candle
* Carcel
* Diya
* Flare
* Gas
* Kerosene
* Lantern
* Limelight
* Oil
* Rushlight
* Safety
* Tilley
* Torch

Electric arc|

* Carbon arc
* Klieg light
* Yablochkov candle

Gas discharge|

* Deuterium arc
* Neon
* Plasma
* Sulfur
* Xenon arc
* Xenon flash

High-intensity
discharge (HID)|

* Mercury-vapor
* Metal-halide
* ceramic
* Hydrargyrum medium-arc iodide (HMI)
* Hydrargyrum quartz iodide (HQI)
* Sodium vapor

* Theatrical
* Cinematic

* Floodlight
* Footlight
* Gobo
* Scoop
* Spotlight
* ellipsoidal reflector
* Stage lighting instrument

Stationary|

* Reflector
* Parabolic aluminized reflector (PAR)
* Multifaceted reflector
* Ellipsoidal reflector
* Aircraft warning
* Balanced-arm lamp
* Chandelier
* Emergency light
* Gas lighting
* Gooseneck lamp
* Intelligent street lighting
* Light tube
* Nightlight
* Neon lighting
* Pendant light
* Recessed light
* Sconce
* Street light
* Torchère
* Track lighting
* Troffer

Mobile|

* Flashlight
* tactical
* Glow stick
* Headlamp (outdoor)
* Lantern
* Laser pointer
* Navigation light
* Searchlight
* Solar lamp

* Industrial
* Scientific

* Germicidal
* Grow light
* Infrared lamp
* Stroboscope
* Tanning

* Display
* Decorative

* Aroma lamp
* Black light
* Bubble light
* Christmas lights
* Crackle tube
* DJ lighting
* Electroluminescent wire
* Lava lamp
* Marquee
* Plasma globe
* Strobe light

Related topics|

* Bioluminescence
* Chemiluminescence
* Electroluminescence
* Laser
* Photoluminescence
* Radioluminescence

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Nightlight. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Engineering:Nightlight&oldid=916922"
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template