Light-emitting diode
Light-emitting diode http://en.wikipedia.org/wiki/Light-emitting_diode A light-emitting diode (LED) is a two-lead semiconductor light source that resembles a basic pn-junction diode, except that an LED also emits light.[7] When an LED's anode lead has a voltage that is more positive than its cathode lead by at least the LED's forward voltage drop, current flows. Electrons are ..