Carbon Zinc battery also known as primary cell or dry cell or pencil cell is among the cheapest reliable power sources powering a large variety of electronic equipments since the last century. It is used to provide a constant voltage source through a chemical reaction. This battery cannot be recharged and has to be disposed after usage. A commonly used primary battery is shown in the image above. These types of batteries are available in various sizes and are used to power devices like Torches, Toys, Remote Control, Clocks etc. The battery has two terminals the top view is the positive terminal and the bottom view is the negative terminal.