Abstract
The author has previously shown that the permanent "homo" charge (of the same sign as the electrode) on electrets arise from a transfer of charge from electrode to dielectric surface, often by discharges. Using the method of the demountable capacitor this discharge process of charge transfer has been investigated on polystyrene. By assuming that breakdown occurs at a given inception voltage, persists until the voltage drops to an extinction voltage, and affects the whole area of the electrode and dielectric surface, a quantitative explanation has been given of the variation of the charges on the electrode and on the dielectric surface when the voltage is varied in steps, in cycles, continuously and alternating. The explanations agree with the current theories of internal and external discharges. The extinction voltage is found to be not much less than the inception voltage, as opposed to the low extinction voltages often encountered in internal discharges.