The chemical reaction starts when you insert a battery into a device and complete the circuit. A battery produces power through a chemical reaction.

A battery produces power through a chemical reaction.

Most chemical reactions produce energy in the form of heat, but - by confining chemicals inside the container and controlling the resulting reaction with a separator - batteries produce electrical energy.

The electrolyte oxidizes the anode's powdered zinc. The cathode's manganese dioxide/carbon mix reacts with the oxidized zinc to produce electricity.

The collector conducts the electric current out of the battery to an external circuit, such as contact points on a flashlight bulb or a portable CD player.

As the battery is used and the zinc (anode) oxidizes, themanganese dioxide (cathode) is reduced.

Interaction between the zinc and the electrolyte produces reaction products, which gradually slows the cell's action and lowers its voltage.

At the same time, the available manganese dioxide depletes, becoming less and less active as a cell cathode. There factors combine to cause a gradual drop in battery's "working or operating voltage"