You need to know how to measure the current that flows through a component in a circuit and the voltage across it. The ammeter must be connected in series with the component – remember, in a series ...

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.

You're probably familiar with the old-fashioned strings of holiday lights that go out completely if one bulb burns out. Although these lights cause hours of frustration during the holidays, they also ...