ELECTROLYTIC CAPACITOR

"A storage device similar to any other type of electrical capacitor. However, only one of its conducting phases is a metallic plate, the other conducting phase is an electrolyte solution. The dielectric is a very thin (passive) oxide film on the surface of the metal (typically aluminum or tantalum) that constitutes one conducting phase of the capacitor. There is also another metal electrode immersed in the solution, which serves only as the electrical contact to the solution. Electrolytic capacitors typically have much larger capacitance than classical capacitors because the dielectric is very thin (on the order of millionth of centimeter). There are no economical ways to produce dielectric films that thin in any other way. The electrolytic capacitor is not to be confused with the electrochemical capacitor. "