Mercury Cell

mercury cell [′mər·kyə·rē ‚sel]

(electricity)

A primary dry cell that delivers an essentially constant output voltage throughout its useful life by means of a chemical reaction between zinc and mercury oxide; widely used in hearing aids. Also known as mercury oxide cell.

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Mercury Cell 

a galvanic cell with a negative electrode of Zn, In, or Cd and a positive electrode of red mercuric oxide and graphite. A solution or paste of potassium hydroxide serves as the electrolyte.

Mercury cells with a liquid electrolyte were already in use during the 1880’s. However, their mass production and widespread use did not become practical until the 1940’s, when their design was improved and new manufacturing techniques were developed. The most widely used mercury cell is designated KhRTs, a mercury-zinc cell in which the negative electrode is made of highly pure zinc. The initial voltage of this cell is 1.25–1.35 volts (V), and the final voltage approximately 1 V. Cells of this design can have capacities from 0.01 to 14.0 ampere-hours and can weigh from 0.2 to 170 g.

Mercury cells are noted for their voltage stability, long shelf life, resistance to mechanical disturbance, and small size. They are used as power sources, for example, in small radios, hearing aids, medical instruments, photographic and cinematographic equipment, and electric clocks, as well as in electro-metric instruments as sources of reference voltage.

REFERENCES

Roginskii, V. Iu. Sovremennye istochniki pitaniia. Leningrad, 1969.
Orlov, V. A. Malogabaritnye istochniki toka, 2nd ed. Moscow, 1970.