The single simple control function system is a repeater system. In power systems, repeaters are usually used to exchange voltages. In addition, it can also be used to exchange current or switch circuits. Repeater usually consists of a mechanical part and a control circuit. The mechanical part can be turned on or off according to a specified control signal, thus switching the circuit. Repeaters are usually used to redirect power lines to other terminals, thus realizing some aspects of power distribution.