A galvanic or voltaic cell or battery is an arrangement in which electricity is yielded by chemical action. Such electricity is named current, because it is continuous while the chemical action lasts, and not intermittent, like the momentary discharge from a Leyden jar.

A current may also be generated by heating the j unction of two dissimilar metals; the electricity obtained in this way is called the thermo-electric current, the heat being transformed into electricity. Another method of obtaining a current is by rotating a coil of wire between the poles of a magnet or of an electromagnet, as in the dynamo which yields electric light and power. The chief subjects which require to be considered under the head of Current Electricity are (1) the effect of the current in producing Z, zinc plate in dilute sulphuric chemical decompositions: acid; P, platinum plate la strong nitric acid. (2) in producing heat and light, as in electric lighting {q.v.); (3) the production of induced currents by the action of anohter current or of a magnet; (4) the measurement of the strength of the current, as with the galvanometer. (See Galvanometer, Ether.)