The Photoconductivity of Zinc‐Cadmium Sulfide as Measured with the Cathode‐Ray Oscillograph

A new method for the measurement of photoconductivity, involving the cathode‐ray oscillograph as a recording instrument, is described. Several interesting aspects of photoconductivity of phosphors, including the quenching effect of red light, are discussed. New evidence in support of the “trapping center” or metastable‐state theory in regard to phosphorescence is presented.