An electrolytic capacitor (e-cap) is a polarized capacitor whose anode or positive plate is made o a metal that forms an insulating oxide layer throu anodization. This oxide layer acts as the dielectric o the capacitor. A solit, liquid, or gel electrolyte covers the surface o this oxide layer, serving as the (cathode) or negative plate o the capacitor. Due tae thair very thin dielectric oxide layer an enlarged anode surface, electrolytic capacitors hae a much higher capacitance-voltage (CV) product per unit volume compared tae ceramic capacitors or film capacitors, an sae can hae lairge capacitance values. Thare are three families o electrolytic capacitor: aluminum electrolytic capacitors, tantalum electrolytic capacitors, an niobium electrolytic capacitors.
The lairge capacitance o electrolytic capacitors maks them parteecularly suitable for passing or bypassing law-frequency signals, an for storing lairge amounts o energy. Thay are widely uised for decoupling or noise filtering in pouer supplies an DC link circuits for variable-frequency drives, for coupling signals atween amplifier stages, an storing energy as in a flashlamp.
Electrolytic capacitors are polarized components due tae thair asymmetrical construction, an must be operated wi a higher voltage (ie, mair positive) on the anode than on the cathode at aw times. For this reason the anode terminal is merked wi a plus sign an the cathode wi a minus sign. In addition thay can anly tolerate law applee'd voltages. Applying a reverse polarity voltage, or a voltage exceedin the maximum rated wirkin voltage o as little as 1 or 1.5 volts, can destroy the dielectric an sicweys the capacitor. The failure o electrolytic capacitors can be hazardous, resultin in an explosion or fire. Bipolar electrolytic (aka non-polarized) capacitors which mey be operated wi aither polarity are special constructions wi twa anodes connected in series.