LED display: We can see all kinds of LED subtitle display in buses and subways, and there are also many large LED dot matrix display screens in the outdoors, which is a relatively clear super-large screen TV from a distance. Here you need to use a special LED display control chip. LED (Light Emitting Diode) is a solid-state semiconductor device that converts electricity directly into light. The heart of the LED is a semiconductor wafer, one end of the wafer is attached to a bracket, one end is a negative electrode, the other end is connected to the positive electrode of the power supply, so that the whole wafer is encapsulated by epoxy resin. A semiconductor wafer is made up of two parts, one is a P-type semiconductor, in which holes dominate, and the other is an N-type semiconductor, in which electrons dominate. But when the two semiconductors are connected, they form a "P-N junction." When an electric current is applied to the chip through a wire, electrons are pushed towards the P-zone, where they combine with holes and emit energy in the form of photons, which is how leds emit light. And the wavelength of light, the color of light, is determined by the material that forms the P-N junction