LED is the abbreviation of the English word Light Emitting Diode. It can directly convert electricity into light. The heart of the LED is a semiconductor chip. One end of the chip is attached to a support, which is the negative pole, and the other end is connected to the positive pole of the power supply. The entire chip is encapsulated by epoxy resin. The semiconductor wafer is composed of two parts, one part is a P-type semiconductor, in which holes dominate, and the other end is an N-type semiconductor, which is mainly electrons. But when these two semiconductors are connected, a "P-N junction" is formed between them. When the current acts on the chip through the wire, the electrons will be pushed to the P area, where the electrons and holes recombine, and then emit energy in the form of photons. This is the principle of LED light emission. The wavelength of light (the color of light) is determined by the material forming the P-N junction.
