A battery gets its name based on the chemical components that react to create the electric current. A zinc-carbon battery utilizes a zinc container to both house the chemicals and serve as the negative terminal in the electric circuit. The carbon rod inside the battery serves as the positive terminal and collects electrons. These batteries are commonly used in small electronic devices and were the first commercially available dry cell battery.
When a battery is connected to a device, the chemicals inside the battery react to create an electric current to charge the device. A zinc-carbon battery has two oppositely charged ends that are marked positive and negative. Electrons accumulate on the negative end and then travel toward the positive end. This creates an electric current in the opposite direction. Electric current flows through the negatively charged terminal into the device to charge it.
In the zinc-carbon battery, the zinc container is the negative terminal through which the electric current flows into the device. The positive terminal is a mixture of chemicals — usually a mixture of manganese dioxide powder, carbon and an electrolyte. A carbon electrode rod also is placed inside the middle of the battery, connecting the two metal-capped ends of opposite charges and serving as the positive terminal. This rod is the means by which the electrons travel. This battery structure makes it able to function in all positions, making it ideal for use in portable electronic devices.
Zinc-carbon batteries were the first commercially available dry battery and are used mostly in small portable electronic devices that require a low to moderate level of power, such as flashlights and cameras. They are available in both a cylindrical and flat cell form. The flat cell form allows for a higher available voltage because of its ability to stack one on top of another and increase the electronic circuit.
A zinc-carbon battery is not rechargeable, but it is disposable and inexpensive. Thousands of zinc-carbon batteries are disposed of each year, sometimes incorrectly. Mercury was originally added to decrease the rate of corrosion inside the zinc-carbon battery. In 1996, the United States banned the use of mercury in batteries, thus significantly reducing the environmental impact of discarded zinc-carbon batteries.