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
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