What is "electrolytic capacitor"

n. (context electronics English) capacitor that uses an electrolyte as one of its capacitative plates

n. a fixed capacitor consisting of two electrodes separated by an electrolyte [syn: electrolytic, electrolytic condenser]

• Aluminum electrolytic capacitors,
• Tantalum electrolytic capacitors and
• Niobium electrolytic capacitors

All electrolytic capacitors (e-caps) are polarized capacitors whose anode (+) is made of a particular metal on which an insulating oxide layer forms by anodization, acting as the dielectric of the electrolytic capacitor. A non-solid or solid electrolyte which covers the surface of the oxide layer in principle serves as the second electrode ( cathode) (-) of the capacitor.

Due to their very thin dielectric oxide layer and enlarged anode surface, electrolytic capacitors have—based on the volume—a much higher capacitance- voltage (CV) product compared to ceramic capacitors or film capacitors, but a much smaller CV value than electrochemical supercapacitors.

The large capacitance of electrolytic capacitors makes them particularly suitable for passing or bypassing low-frequency signals up to some mega-hertz and for storing large amounts of energy. They are widely used for decoupling or noise filtering in power supplies and DC link circuits for variable-frequency drives, for coupling signals between amplifier stages, and storing energy as in a flashlamp.

Standard electrolytic capacitors are polarized components due to their asymmetrical construction, and may only be operated with a higher voltage (ie, more positive) on the anode than on the cathode at all times. Voltages with reverse polarity, or voltage or ripple current higher than specified (as little as 1 or 1.5 volts may suffice), can destroy the dielectric and thus the capacitor. The destruction of electrolytic capacitors can have catastrophic consequences (explosion, fire).

Bipolar electrolytic (aka non-polarized) capacitors which may be operated with either polarity are special constructions with two anodes connected in reverse polarity.