Galvanic cell bridge zinc ions leave and anions enter the zinc half-cell. In the copper half-cell, the copper ions plate onto the copper electrode (reduction), taking up electrons that leave the external conductor. Since the Cu ions (cations) plate onto the copper electrode, the latter is called the cathode. Correspondingly the zinc electrode is the anode. The electrochemical reaction is: In addition, electrons flow through the external conductor, which is the primary application of the galvanic cell. As discussed under #Cell voltage, the emf of the cell is the difference of the half-cell potentials, a measure of the relative ease of dissolution
Silver chloride electrode or electrochemically by oxidising the silver in a chloride solution. A porous plug on one end allows contact between the field environment with the silver chloride electrolyte. An insulated lead wire connects the silver rod with measuring instruments. A voltmeter negative lead is connected to the test wire. The electrode body contains potassium chloride to stabilize the silver chloride concentration. When working in seawater, this body can be removed and the chloride concentration is fixed by the stable salinity of the water. The potential of a silver:silver chloride reference electrode with respect to the standard hydrogen electrode depends on the