Fig. 45.
56a. Bunsen Cells, Fig. 45, are used for motors, small incandescent lamps, etc. A carbon rod is inclosed in a porous cup, on the outside of which is a cylinder of zinc that stands in dilute sulphuric acid, the carbon being in nitric acid.
57. The Leclanché Cell is an open circuit cell. Sal ammoniac is used as the exciting fluid, carbon and zinc being used for plates. Manganese dioxide is used as the depolarizer; this surrounds the carbon plate, the two being either packed together in a porous cup or held together in the form of cakes. The porous cup, or pressed cake, stands in the exciting fluid. The E. M. F. is about 1.5 volts.
Fig. 46.
Fig. 47.
Fig. 48.