A circuit may refer to any of the following:
1. In electronics, a circuit is an electronic component consisting of a complete path: a voltage source and a load.
2. With a telephone and wireless communication, a circuit is a persistent and dedicated connection for transmitting data or voice information.
3. With power, a circuit or power circuit is a circuit that carries the load of power to appliances and devices on a line. In your home, the lighting outlets are power circuits because they only provide power when they are turned on.
A power circuit is different from a control circuit.