The power adapter is a small portable electronic device and a power conversion device for electronic appliances. It is generally composed of components such as a housing, transformer, inductor, capacitor, control IC, and PCB board. Its working principle is to convert AC input to DC output; According to the connection method, it can be divided into wall type and desktop type. It is widely used in security cameras, set-top boxes, routers, light bars, massage machines, and other equipment.