A general method of determining the equivalent circuit elements of a network containing any number and arrangement of resistances with one variable impedance element involves plotting a graph of the reactive component of the impedance against the resistive component at different frequencies. Capacitance bridge measurements at audio‐frequencies with a Weston Photronic cell at different illuminations yield data for such a graph. Circles are obtained from which it is concluded that the impedance element itself is capacitative and maintains a constant phase difference of the order of magnitude of 10° between current and voltage. The impedance of the cell as a whole decreases radically with frequency. From the circles it is found that the equivalent resistance in series with the impedance element is of the order of 35 ohms and is independent of illumination and other variable factors. The equivalent resistance in parallel with the impedance element is of the order of several thousand ohms, decreases with illumination and varies from day to day. After illumination, more than ten minutes elapse before steady conditions are again attained in the dark. The impedance element itself is regarded as capacitance of the order of 0.5&mgr;f and a series resistance, each decreasing with frequency. The capacitance varies approximately inversely as the frequency raised to the 0.1 power, and the resistance inversely as the frequency raised to the 0.9 power. Fricke's equation relating the former exponent to the phase difference is found applicable. The capacitance increases and the resistance decreases with illumination. A general similarity to electrolytic polarization capacitance is noted. When an inductance coil is placed across the cell and the cell is illuminated with light of sinusoidally‐varying intensity, resonance is obtained at a definite critical frequency.