A light-emitting-diode (LED) (pronounced /??Li??Di?/),[1] is a semiconductor diode that emits light when an electric current is applied in the forward direction of the device, as in the simple LED circuit. The effect is a form of electroluminescence where incoherent and narrow-spectrum light is emitted from the p-n junction.

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A semiconductor light source that emits visible light or invisible infrared radiation.

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Work on a completely different concept. Traditionally leds are created from two semiconductors. By running current in one direction across the semiconductor the led emits light of a particular frequency (hence a particular color) depending on the physical characteristics of the semiconductor used. The semiconductor is covered with a piece of plastic that focuses the light and increases the brightness. These semiconductors are very durable, there is no filament, they donÕt require much power, theyÕre brighter and they last a long time. By densely packing red, blue and green leds next to each other on a substrate one can create a display

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Work on a completely different concept. Traditionally leds are created from two semiconductors. By running current in one direction across the semiconductor the led emits light of a particular frequency (hence a particular color) depending on the physical characteristics of the semiconductor used. The semiconductor is covered with a piece of plastic that focuses the light and increases the brightness. These semiconductors are very durable, there is no filament, they donít require much power, theyíre brighter and they last a long time. By densely packing red, blue and green leds next to each other on a substrate one can create a display. The disadvantage of leds is that they are much larger ñ therefore the resolution is not nearly as good as lcd displays. That's why most led displays are large, outdoor displays, not smaller devices, like monitors.

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