Series and parallel circuits

A dipole is an electrical conductor with two poles (also called terminals). An electric circuit is an association of dipoles connected to one another by conducting wires.

In order for a current to flow in the circuit, one of the dipoles must be a source of current (generator) and the circuit must be closed.

• Two dipoles are in series when they share only a single terminal and, between shared terminals, there is no branching toward another dipole.
• Two dipoles are in parallel (or in a branched circuit) if their two pairs of terminals are shared.