Light-emitting diode
A light-emitting diode (LED) is an electronic component that uses a semiconductor to emit light when current flows through it. Electrons in the semiconductor recombine with electron holes, thereby releasing energy in the form of photons. The color of the light is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device.
On WikiTrade, every Wikipedia article is a card: the more the article is read, the rarer the card. Open free packs, complete your album, trade, bid and challenge others to general-knowledge duels.
Play for freeRead the article on WikipediaText from Wikipedia (CC BY-SA 4.0). WikiTrade is an independent site, not affiliated with Wikipedia or the Wikimedia Foundation.