a light emitting diode (LED) can emit infrared, visible light of almost any colour or near ultraviolet
A light emitting diode (LED) is a
semiconductor that emits a
narrow-spectrum radiation when an
electric current flows through it in the
forward direction. This emission is a form
of electroluminescence and the
wavelength of the emitted radiation
depends on the composition of the
semiconductor material. It can be
infrared, visible light of almost any colour
or near ultraviolet. Unlike incandescent
bulbs, LED's do not have a filament and
they do not get especially hot. The power
consumption of a single LED is typical 20 mW and a package or array of LED's
consumes significant less energy than any incandescent lamp with a comparable
yield. The light emission of a LED is solely caused by the movement of electrons in a
semiconductor material and its lifetime is just as long as that of an average transistor,
which easily can be a quarter of an age.