Aluminum electrolytic capacitor Aluminum electrolytic capacitor Aluminum electrolytic capacitors are polarized electrolytic capacitors whose anode electrode (+) is made of a pure aluminum foil with an etched surface. The aluminum forms a very thin insulating layer of aluminium oxide by anodization that acts as the dielectric of the capacitor. A non-solid electrolyte covers the rough surface of the oxide layer, serving in principle as the second electrode (cathode) (-) of the capacitor. A second aluminum foil called “cathode foil” contacts the electrolyte and serves as the electrical connection to the negative terminal of the capacitor. Aluminum electrolytic capacitors are divided into three subfamilies
Electrolytic capacitor relatively high capacitance values of electrolytic capacitors compared with other capacitor families. Because the forming voltage defines the oxide layer thickness, the desired voltage rating can be produced very simply. Electrolytic capacitors have high volumetric efficiency, the so-called "CV product", defined as the product of capacitance and voltage divide by volume. Combinations of anode materials for electrolytic capacitors and the electrolytes used have given rise to wide varieties of capacitor types with different properties. An outline of the main characteristics of the different types is shown in the table below. The non-solid or so-called "wet" aluminum electrolytic capacitors were and