The light emitting diode is composed of a III-V compound, such as GaAs (Shen Huajia), GaP (Lin Huajia), GaAsP (P Shen Huajia), made of a semiconductor, its core is the PN junction. So it is with the characteristics of I-N P-N node, namely the forward conduction, stop, reverse breakdown characteristics. In addition, under certain conditions, it also has the light emitting characteristics. In the forward voltage electron by N injected into the P region, the hole injection N zone by P. Minority carrier into the area of the other side (Shao Zi) part of the majority carrier (multi) compound and light emitting.