Grocery Store Cells and Batteries

The cells you see in grocery stores, department stores, drugstores, and hardware stores provide 1.5 V, and are available in sizes known as AAA (very small), AA (small), C (medium large), and D (large). Batteries are widely available that deliver 6 or 9 V.

Zinc-Carbon Cells

Following Figure is a translucent drawing of a zinc-carbon cell. The zinc forms the case and is the negative electrode. A carbon rod serves as the positive electrode. The electrolyte is a paste of manganese dioxide and carbon. Zinc-carbon cells are inexpensive and are good at moderate temperatures and in applications where the current drain is moderate to high. They are not very good in extreme cold.

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Alkaline Cells

The alkaline cell has granular zinc as the negative electrode, potassium hydroxide as the electrolyte, and a device called a polarizer as the positive electrode. The construction is similar to that of the zinc-carbon cell. An alkaline cell can work at lower temperatures than a zinc-carbon cell. It lasts longer in most electronic devices, and is therefore preferred for use in transistor radios, calculators, and portable cassette players. Its shelf life is much longer than that of a zinc-carbon cell. As you might expect, it costs more.

Transistor Batteries

A transistor battery consists of six tiny zinc-carbon or alkaline cells in series. Each of the six cells supplies 1.5 V. Thus, the battery supplies 9 V. Even though these batteries have more voltage than individual cells, the total energy available from them is less than that from a C cell or D cell. This is because the electrical energy that can be obtained from a cell or battery is directly proportional to the amount of chemical energy stored in it, and this, in turn, is a direct function of the volume (physical size) of the cell or the mass (quantity of chemical matter) of the cell. Cells of size C or D have more volume and mass than a transistor battery, and therefore contain more stored energy for the same chemical composition.

Transistor batteries are used in low-current electronic devices such as remote-control garagedoor openers, television (TV) and hi-fi remote controls, and electronic calculators.

Lantern Batteries

The lantern battery has much greater mass than a common dry cell or transistor battery, and consequently it lasts much longer and can deliver more current. Lantern batteries are usually rated at 6 V, and consist of four good-size zinc-carbon or alkaline cells. Two lantern batteries connected in series make a 12-V battery that can power a 5-W citizens band (CB) or ham radio transceiver for a while. They’re also good for scanner radio receivers in portable locations, for camping lamps, and for other medium-power needs.