An electric current is a flow of charge. When a torch is switched on electrons flow through the torch bulb and cell. Metals contain delocalised electrons which move freely between the metal ions. The electrons prevent the positive ions from repelling each other. Electrons flow through the bulb because its filament is made of metal, and the electrons transfer energy from the cells to the bulb.
The size of an electric current is the rate of flow of electric charge, which is the flow of charge per second. The current depends on the quantity of electrons passing through a component. An electric charge is measured in coulombs (C) and an electric current in amperes (A). An electric current of one ampere is a rate of flow of charge of 1 coulomb per second.
