A light-emitting diode (LED) is a semiconductor device that produces light from electricity. LEDs last a long time and do not break easily (compared to incandescent lightbulbs). They can produce many different colors. They are efficient - most of the energy makes light, not heat.
An LED is a type of diode that makes one color of light when electricity is sent through it in the expected direction (electrically biased in the forward direction). This effect is a kind of electroluminescence.
The color of the light depends on the chemical composition of the semiconducting material used, and can be near-ultraviolet, visible or infrared. The color affects how much electricity is used by the LED. A white LED has either two or three LEDs inside, of different colors. Some white LEDs have one single-color LED inside, combined with a phosphor that converts that single color to white.

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