The word battery is often misunderstood and misused. Strictly, a battery is two or more single cell sources of electricity. For example, a 1.5v unit is called a cell, whereas a 4.5v unit is called a battery, i.e. three 1.5v cells. However, not all cells have a voltage of 1.5v. A cell is the basic unit that produces electricity and has three main sections. There is a negative electrode, a positive electrode and a mixture of chemicals called the electrolyte. A battery produces an electrical charge when chemical reactions in the cell cause electrons to flow out of the negative electrode, around the circuit, together with any devices in the circuit, and back via the positive electrode. As soon as the circuit is broken, the chemical reactions stop and the flow of electrons cease. Batteries are convenient sources of electrical energy and have a variety of everyday uses.
