Light Emitting Diode (LED)
A diode that emits light when current is passed through it. It has two leads: cathode (k) and anode. When forward-biased, free electrons combine with holes near the junction. As they move from an area of higher energy to lower energy, they emit radiation.
The light that is emitted is incoherent.
Depending on the material used to make the diode, the light may be red, green, blue, white or amber.