Element Volta

In the 18th century. L. Galvani believed that the muscles of animals produce electricity. For example, the foot of a frog, suspended on a copper wire, twitches, touching the iron. Alesandro Volta did not agree with this. He proved that the electricity here is obtained because of the contact of two different metals: the frog's foot serves only as a sensitive device for its detection.

For this purpose, in 1799 Volta manufactured the first electric battery, called the Volta pole. The Element Volta consisted of silver (later copper) and zinc plates, strung on a non-conducting rod; between the plates were gaskets moistened with weak sulfuric acid. The first and last plate was connected to the wires. Each pair of plates produced 1,1 V.

After the discovery of the voltaic pole, Volta became famous throughout the world. In honor of Volta, a voltage unit was named. True, all sources of electricity, like the one described, began to be called galvanic elements, although Galvani was mistaken.

Meanwhile, galvanic elements like the Volta element existed several thousand years ago, and they were found during excavations near Baghdad by archaeologist V. Koenig before the Second World War. He found a lot of clay glazed vessels, each of which contained a copper cylinder and an iron rod, which was a galvanic cell. They determined that they were poured with vinegar, and sealed with bitumen. Apparently, such batteries in ancient times were used for galvanic gilding of small silver ornaments.

All galvanic cells of that time contained a liquid electrolyte: a solution of sulfuric acid, as in a Volta element, or vinegar, as in an ancient battery. This was inconvenient: since the Volta element could lose its integrity upon impact.

There was one more drawback of the Volta element - he got tired very quickly - he started giving currents of lower values. The reason was that the copper plates were covered with hydrogen bubbles, which was released during the operation of the element; while the active surface of the metal was greatly reduced.

To eliminate all these shortcomings, the Frenchman Leclanche came up with an element that serves us until now. In the zinc sleeve is placed electrolyte - a solution of ammonia (ammonium chloride), there is also dropped a carbon rod, wrapped in gauze with manganese peroxide in it. Thus, the carbon rod, although located in the electrolyte, but the latter penetrates to it only through a layer of manganese peroxide, which absorbs hydrogen released on the carbon electrode. As a result, the element of Leclanche almost "does not get tired" until the very end of the term.

It remains to add that the electrolyte in modern elements of Leclanche is not liquid, but in the form of a paste or thick jelly. Then, even if the housing is damaged, the liquid does not leak.