Light-Emitting Diode

A light-emitting diode, or LED, is an electronic component that uses a semiconductor to emit light when current flows through it, as electrons and holes recombine inside the material and release their energy as photons whose color depends on the semiconductor's band gap. The English engineer Henry Joseph Round first reported electroluminescence in a semiconductor in 1907, and the Russian scientist Oleg Losev studied the same effect independently in the 1920s, but the American engineer Nick Holonyak Jr. built the first practical visible-light LED, emitting red light, at General Electric in 1962. LEDs have since expanded from a dim red indicator light into a family of devices spanning infrared, visible and ultraviolet wavelengths, valued for their low power consumption, long lifespan and compact size, and now used for everything from household lighting to digital displays.