A parallel circuit is way of connecting components on separate branches, so the current can take different routes around the circuit. The current is different in different parts of a parallel circuit.

The simplest complete circuit is a piece of wire from one end of a battery to the other. An electric current can flow in the wire from one end of the battery to the other, but nothing useful happens.

Last month's column covered the behavior of electrical components connected in series and demonstrated that when a voltage is applied across a series circuit, the current through each component is the ...