SMD Aluminum Capacitors

An aluminum electrolytic capacitor is constructed from two conducting aluminum foils, one of which is coated with an insulating oxide layer and a paper spacer soaked in electrolyte. The foil insulated by the oxide layer is the anode, while the liquid electrolyte and the second foil acts as the cathode. The surface mount versions of the aluminum capacitor can be mounted directly on the surface of the PCB without the need of extended contacts.