: Galvanic or voltaic cells are those cells where electrical energy is produced by chemical reactions of substances inside the cell. In galvanic cells, usually two electrodes made up of two different elements are partially immersed in an electrolytic solution in two different containers. The electrode between the two electrodes acts as the anode of the more active metal and the electrode of the less active metal as the cathode. The electric gate of the metal with which the corner electric gate is made must be placed in an electrolytic that contains ions of that metal in the electrolyte. For example, if an electric gate is made of a copper bar, the bar is placed in a solution of CuSO4 electrolysis. Again , if an electric gate is made of a zinc metal bar, that bar is placed in a solution of ZnSO4 electrolysis. When two electric gates are connected to a metal wire from the outside, electrons flow from one electric gate to the other, creating an electric current. A U -shaped salt bridge is placed between the two electrolytic solutions . A U -shaped glass contains a solution of KCl salt.