Influence of discharge conditions on the charge decay characteristics

A simplified analysis of the charge decay processes for samples equipped with different types of grounding electrodes is presented. It is shown that the electrical properties of the back electrode (injecting or blocking) can strongly influence the charge decay process for plane parallel dielectric samples. The theory is confirmed by experimental investigation. For the sample with blocking back electrode the 50% time decay parameter can be an order of magnitude higher compared to that obtained for injecting or side electrode. In practical situations charge decay with the plane parallel samples may be much slower than that predicted by measurements carried out according to current standards.