A complete circuit must have:

• a power source (battery) and

• a path for the electric current, such as a wire, to flow through.

A closed circuit occurs when the path along which the electrical current flows must not be broken or opened anywhere along the way.

Sometimes, we will see a switch added to a circuit. For electricity to continue to flow, the switch must be closed.

When we flip the switch off (or open the switch), we open the circuit and stop the flow of the electricity, the path is open, which stops electricity flow and stops it from completing its path.