Comparison between the PEA method and the PWP method for space charge measurement in solid dielectrics

The principles of both pulsed electro acoustic (PEA) and pressure wave propagation (PWP) methods for measuring the space charge distributions in solid dielectrics are summarized. The relationship between the charge distribution in a specimen and voltage signal of the PEA method or the current signal of the PWP method are expressed in the time and frequency domains. Furthermore, the calibration method of the amount of accumulated charge density using deconvolution techniques is described for both methods. To compare these two methods, PMMA samples with and without space charge are measured using both methods. In addition, the electric field and electric potential distributions are calculated and discussed. The experimental results obtained using both methods are almost the same.