An electric circuit is a closed path through electrically conducting materials. A circuit consists of electrical elements like a resistor, capacitor, inductor, a switch, and battery (emf). These elements are connected in a series using a copper wire from one end of an element to one end of next element in the circuit. Some elements can be connected in parallel circuit with the battery or another element.
The battery maintains higher potential at the positive terminal as compared to the negative terminal. When the switch is closed, due to the electric field created by the potential difference, the current of positive charges passes from positive terminal of battery towards the negative terminal. Equivalently, electrons move from negative terminal to the positive terminal.
At home, the main power supply is connected in parallel to various appliances and lamps.
A circuit is broken if a part of the circuit is broken or disconnected.
See diagram for an example.