Electrolytic capacitor

An electrolytic capacitor is a polarized capacitor whose thin oxide dielectric and electrolyte enable high capacitance in a compact package. Its polarity must be respected in ordinary operation.

Capacitance: Capacitance is a measure of how much electric charge a system stores per unit voltage. A very thin dielectric and large effective electrode area produce the high capacitance.
Aluminum electrolytic capacitor: An aluminum electrolytic capacitor uses etched aluminum foil and an aluminum oxide dielectric. It is the most common electrolytic design in power supplies and general electronics.
Rectifier: A rectifier converts alternating current into unidirectional current. Electrolytic capacitors commonly smooth the rectifier’s pulsating output.
Capacitor: A capacitor is a passive electrical component that stores energy in an electric field. Electrolytic capacitors are one polarized, high-capacitance branch of this broader component family.
Dielectric: A dielectric is an electrically insulating material that polarizes in an applied electric field. The capacitor’s oxide layer serves as the dielectric between its electrodes.
Tantalum capacitor: A tantalum capacitor is a polarized electrolytic capacitor that uses tantalum pentoxide as its dielectric. Its compact construction offers high capacitance, with distinct surge and failure constraints.
Power supply: A power supply converts electrical energy into voltages and currents suited to a load. Large electrolytic capacitors store energy and reduce output ripple in many supplies.
Supercapacitor: A supercapacitor stores energy through electric double layers or fast surface redox reactions. It can provide far greater capacitance, but generally operates at much lower voltage per cell.
Anodization: Anodization is an electrochemical process that forms or thickens an oxide layer on a metal surface. It creates the thin insulating oxide that acts as the dielectric.
Bipolar electrolytic capacitor: A bipolar electrolytic capacitor is designed to tolerate alternating voltage without a fixed terminal polarity. Its back-to-back oxide structure permits AC use where ordinary polarized units are unsuitable.

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TantalumNarrower topic: Tantalum capacitors are one metal-specific member of this capacitor family.