(1) Power transformer: This is a kind of soft magnetic electromagnetic component. Its function is to transform the power transmission voltage and isolate it. Power transformer has been widely used in power technology.

(2) Rectifier circuit: the function of rectifier circuit is to convert alternating current into direct current. Generally, rectifier circuit is composed of transformer, rectifier main circuit and filter. It is widely used in DC motor excitation regulation, electroplating and other fields.

(3) Filter circuit: the filter circuit can filter out the ripple in the rectified output voltage. It is composed of reactance components, such as shunt capacitors at both ends of the load resistance, and a compound filter circuit composed of inductors and capacitors.

(4) Voltage stabilizing circuit: the voltage stabilizing circuit is a circuit that can still provide a stable and constant voltage with the changes of voltage, load, ambient temperature and circuit parameters. Such a DC voltage stabilizing power supply has been adopted by most electronic devices now.