Measurement of the Current Generated by a Rectifier Photoelectric Cell

Abstract

CAMPBELL and Freeth¹ have described a method of measuring the current generated by a rectifier cell in such a way as to reduce greatly the disturbing effect of the internal leakage which occurs in these cells. This varies with temperature and intensity of illumination and may cause large curvature of the light-current characteristic in strong light. This method consists in the insertion of a variable external source of potential, obtained from a potentiometer arrangement, in series with the cell and the galvano meter or micro-ammeter, M, used for measuring the current, and the connexion of a second galvanometer, G, directly across the terminals of the cell. The potentiometer is adjusted until a zero reading of G is obtained. M then measures the current, and the absence of potential difference between the cell terminals greatly reduces leakage currents, though small internal potential differences may occur between the back plate and parts of the front conducting film, which cannot be at the same potential throughout owing to its appreciable resistance.