2006-12-28 03:03:11 · 4 answers · asked by nicholastan_tlk 1 in Science & Mathematics ➔ Engineering
LED is short for light emmiting 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. The color of the emitted light depends on the composition and condition of the semiconducting 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 [1] 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
2006-12-28 03:15:15 · answer #1 · answered by Joe G 2 · 1⤊ 0⤋
LED stands for light emitting diode.
Basically, it is a diode who's output is light.
Since it's a diode, it is basically a one way valve. By applying a voltage across the diode (usually above 0.7 volts) the diode turns on and therefore emits light. If the voltage is lower than 0.7 volts, or is negative, the diode will turn off and not allow any current to flow through it and the light will be off.
LEDs have many applications from traffic signals to electronic devices. Typically, they are used to convey some sort of information. For example, an LED on a button or above a button may turn on to indicate that the button was pressed and its function is operational.
Hope this helps.
2006-12-28 05:17:30 · answer #2 · answered by squang 3 · 0⤊ 0⤋
LED is short for Light Emitting Diode.
Passing an electric current through the diode causes it to light up.
TVs use a technique call rastering to display a picture starting from the top left corner to the bottom right corner. Scanning in a zig zag pattern from left to right. Each little pixel is light up one at a time which creates a picture.
LED's do the same thing but with diodes, which uses less power than a CRT does.
2006-12-28 03:20:22 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Squang's suggestion of "applying a voltage across the diode" is not correct.
An l.e.d. is a current operated device.
Read this http://www.davidbridgen.com/leds.htm
2006-12-28 09:49:07 · answer #4 · answered by dmb06851 7 · 0⤊ 0⤋