A generator works very much the same as you saw in the experiment. Inside a generator is a magnet, some electrical wire, and a source of mechanical energy. The mechanical energy moves the wire into the magnetic field of the magnet so that the wire cuts through the magnetic lines of force. As a result, electric current is produced. Electric generators can come in all sizes. Some electric generators are very big and contain huge magnets so they can produce a lot of electricity. On the other hand, some generators contain small magnets and are small enough to hold in your hand. These small generators may produce only enough electricity to light one small light bulb.