Edge capacitance in the measurement of dielectric properties

The correction for edge capacitance, which is usually calculated by Kirchhoff´s formula, can be separated by graphical methods into components at various distances from the edge, and so into components which fall within the area of a disc specimen and those which are entirely outside it. In this way, it can be shown that the correction for edge capacitance is usually negligible when permittivity is measured by the adjustment of electrode separation so as to restore the capacitance, after removal of the specimen, to its previous value. The correction to be applied to the observed value of loss tangent is typically about ¿3% of the loss tangent. The paper is a companion to that by Blanco White (p. 939).