An automobile battery is an example of a wet cell battery, with six cells. The cells are connected by short heavy straps from the positive plates of one cell to the negative plates of the adjacent cell. A pair of heavy terminals, plated with lead to resist corrosion, are mounted at the top, sometimes the side, of the battery. During discharge, at the negative terminal a chemical reaction releases electrons to the external circuit, and at the positive terminal another chemical reaction absorbs electrons from the external circuit. This drives the electrons through the external circuit wire to produce an electric current . As the battery discharges, the acid of the electrolyte reacts with the materials of the plates, changing their surface to lead sulfate. When the battery is recharged, the chemical reaction is reversed: the lead sulfate reforms into lead dioxide. With the plates restored to their original condition, the process may be repeated.