LED is simply referred to as LED,Made of compounds containing Ga, As, P, and N.It is a kind of semiconductor diode,Can convert electrical energy into light energy.The light emitting diode is composed of a PN junction just like an ordinary diode,Also has unidirectional conductivity.When a forward voltage is applied to the light emitting diode, holes injected from the P region to the N region and electrons injected from the N region to the P region are separated from the electrons of the N region and the P region by a few microns in the vicinity of the PN junction. Cave compound, producing spontaneous radiation fluorescence.