Electric current

One end of a battery has a positive charge and one end has a negative charge, because of chemical reactions inside it. A battery pushes electric charge (electrons) one way round a complete circuit. There are electric charges in all atoms of the wires and components in a circuit, even when it is not turned on. When a circuit is turned on, electrons everywhere in the circuit start moving at the same time. Individual electrons move round a circuit slowly, at a speed of just a few millimetres each second.