Batteries
TYPES OF BATTERIES
Nickel-Cadmium Cell
The nickel-cadmium cell is a secondary cell, and the electrolyte is potassium hydroxide. The
negative electrode is made of nickel hydroxide, and the positive electrode is made of cadmium
hydroxide. The nominal voltage of a nickel-cadmium cell is 1.25 volts. The nickel-cadmium
battery has the advantage of being a dry cell that is a true storage battery with a reversible
chemical reaction (i.e., it can be recharged). The nickel-cadmium battery is a rugged, dependable
battery. It gives dependable service under extreme conditions of temperature, shock, and
vibration. Due to its dependability, it is ideally suited for use in portable communications
equipment.
Edison Cell
In an edison cell the positive plate consists of nickel and nickel hydrate, and the negative plate
is made of iron. The electrolyte is an alkaline. Typical voltage output is 1.4 volts, and it should
be recharged when it reaches 1.0 volts. The edison cell has the advantage of being a lighter and
more rugged secondary cell than a lead-acid storage battery.
Mercury Cell
Mercury cells come in two types; one is a flat cell that is shaped like a button, while the other
is a cylindrical cell that looks like a regular flashlight battery. Each cell produces about
1.35 volts. These cells are very rugged and have a relatively long shelf life. The mercury cell
has the advantage of maintaining a fairly constant output under varying load conditions. For this
reason, they are used in products such as electric watches, hearing aids, cameras, and test
instruments.
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