Each electronic device has a power supply circuit that supplies energy. The power supply circuit has three kinds of rectifier power supply, inverter power supply and frequency converter. Most common household appliances use DC power supplies. The simplest way to supply a DC power source is with a battery. But batteries have the disadvantages of high cost, large size, and need to be replaced from time to time (the battery should be recharged frequently), so the most economical, reliable and convenient is to use the rectifier power supply.
The power electronic circuit is generally low voltage DC power, so in order to transform from the 220 volt power into DC power, should be the first to 220 volts AC into low-voltage AC into DC rectifier circuit, and pulse, DC can be finally used AC component DC filter circuit to filter the pulse. Some electronic equipment on the quality of the power supply is very high, so sometimes need to add a voltage regulator circuit. Therefore, the composition of rectifier power usually has four parts.