A Mathematical Approach to the C‐V Product in Aluminum Electrolytic Capacitors

Abstract

A mathematical model is developed based on a step distribution in the radii of tunnels of etched aluminum foil for electrolytic capacitors which permits calculating the dependence of the C‐V product (capacitance x voltage) with the anodization voltage. The calculation is based upon a knowledge of the parameters characterizing the distribution. These parameters, namely mean length and radius, width and density of the tunnels of the etched foil, can be easily obtained in the case of high voltage foil by scanning electron microscopy observations. For low voltage foil it is difficult to experimentally define the parameters characterizing the distribution, and therefore the problem must be handled inversely, i.e., the parameters of the distribution function in the radii of the tunnels have been calculated from the experimental C‐V curve.