ABSTRACT
Alternating current (AC) is used in greater quantities than direct cur- rent (DC); however, many important operations are dependent upon DC power. Industries use DC power for many specialized processes. Electroplating and DC variable-speed motor drives are only two examples that show the need for DC power to sustain industrial operations. The conversion of chemical energy into electrical power can be accomplished by the use of electrochemical cells. A cell is composed of two dissimilar metals, which are immersed in a conductive liquid or paste called an electrolyte. The operational principle of a primary cell involves the placing of two unlike conductive materials called electrodes into a conductive solution called an electrolyte. An important characteristic of a chemical cell is its internal resis- tance. Since a cell conducts electrical current, its resistance depends on its cross-sectional area, the length of its current path, the type of materials used, and the operational temperature.
