LED (Light emitting diode), a light-emitting diode, is a solid-state semiconductor device capable of converting electrical energy into visible light, which converts electricity directly into light. The heart of the LED is a semiconductor chip, one end of the chip is attached to a bracket, the other end is the negative electrode, the other end is connected with the cathode of the power supply, so that the whole wafer is encapsulated by epoxy resin.
The semiconductor chip consists of two parts, one part is the P-type semiconductor, the hole in it occupies the dominant position, the other end is the N-type semiconductor, here mainly is the electron. But when the two semiconductors are connected, they form a n knot. When the current is acting on the chip through the wire, the electrons are pushed to the P area, where the electrons are combined with the holes in the P area, and then the energy is emitted in the form of photons, which is the principle of LED light emitting. The wavelength of light is the color of light, which is determined by the material forming the n knot.