What is an LED - Light Emitting Diode

A light-emitting diode (LED) is a semiconductor device that emits incoherent narrow-spectrum light when electrically biased in the forward direction.

This effect is a form of electroluminescence. LEDs are small extended sources with extra optics added to the chip, which emit a complex intensity spatial distribution.

The color of the emitted light depends on the composition and condition of the semi-conducting material used, and can be infrared, visible or near-ultraviolet.

Rubin Braunstein of the Radio Corporation of America first reported on infrared emission from gallium arsenide (GaAs) and other semiconductor alloys in 1955.

Experimenters at Texas Instruments, Bob Biard and Gary Pittman, found in 1961 that gallium arsenide gave off infrared (invisible) light when electric current was applied.

Biard and Pittman were able to establish the priority of their work and received the patent for the infrared light-emitting diode.
Nick Holonyak Jr. of the General Electric Company developed the first practical visible-spectrum LED in 1962.

Definition from Wikipedia: http://en.wikipedia.org/wiki/LED

LED Information and Resources

To learn more about LED lighting, you can also click through to these resources:

LED Lighting Institute - Learn about LED lighting with this three-day course offering by The Lighting Research Center
- Next LED Class begins: May 16-18th - Registration Information
LED Lighting in Freezer Cases - article by Jenifer Brons - Download LED Lighting PDF
Strategies in Light - Annual LED Lighting Conference Focusing on LED Lighting - Event Registration
Residential Landscape Lighting and Design - Resources for landscape lighting
Lightfair International 2007 - New York City Trade Show - May 16-18, 2007 - Signup
Lighting Resource - Directory of Lighting Information
AEC Info - Resources for Architects, Engineers and Contractors - Lighting Manufacturers