It’s easy to take your home electrical system for granted — until it stops working. No one wants to be without light, air conditioning or a working refrigerator, so you might be tempted to ...

Current transfers energy around circuits. Circuit components have various properties that can be measured and then used to make circuits for control and also circuits for testing other components.

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.