Electrode Whewell at Faraday's request). The anode is now defined as the electrode at which electrons leave the cell and oxidation occurs (indicated by a minus symbol, "−"), and the cathode as the electrode at which electrons enter the cell and reduction occurs (indicated by a plus symbol, "+"). Each electrode may become either the anode or the cathode depending on the direction of current through the cell. A bipolar electrode is an electrode that functions as the anode of one cell and the cathode of another cell. A primary cell is a special type of electrochemical cell in which the
Aluminum electrolytic capacitor sensitive to voltages spikes or current surges. The anodic generated insulating oxide layer is destroyed if the polarity of the applied voltage changes. Every electrolytic capacitor in principle forms a "plate capacitor" whose capacitance is greater the larger the electrode area A and the permittivity ε, and the thinner the thickness (d) of the dielectric. The capacitance is proportional to the product of the area of one plate multiplied with the permittivity, divided by the thickness of the dielectric. Electrolytic capacitors obtain their large capacitance values by a large area and small dielectric thickness. The dielectric thickness of electrolytic capacitors