FaradNet

Glossary of Capacitor Terms

Anode: An electrode through which current enters any nonmetallic conductor. An electrolytic anode is an electrode at which negative ions are discharged, or positive ions are formed, or at which other oxidizing reactions occur. The positive electrode of a galvanic cell; of an electrolytic capacitor.

Anode Foil: An aluminum electrolytic capacitor is typically composed of an anode foil, a cathode foil and separator material which are wound together and impregnated with an electrolyte. The anode foil has an aluminum oxide layer acting as the dielectric. After the aluminum foil (65 to 100 microns) is electrochemically etched to increase it's surface area, the dielectric is produced by anodic oxidation of its surface.
Increasing the surface area of the foil serves to increase its unit capacitance after it is anodized.

Anodize: Anodize, formation, or forming process. When immersed in certain electrolyte solutions and connected to a DC power source as an anode with the solution as a cathode, the surface layer of the "valve" metal forms an impervious, amorphous film of oxide having the property of restricting the flow of current in one direction and permitting it to flow in the opposite direction (i.e., a rectifing characteristic).; Common capacitor metals (and dielectrics) are aluminum (Al₂O₃) and tantalum (Ta₂O₅). Other valve metals are zinc and magnesium.

Updated: 24 March 2000