Comparison between the PEA method and the PWP method for measuring space charge distributions

The principles of both the pulsed electro-acoustic (PEA) method and the piezo-electric induced pressure wave propagation (PIPWP) method for measuring the space charge distributions in solid dielectrics were summarized. The relationship between the charge distribution in a specimen and the voltage signal obtained from PEA method or the current signal obtained from PIPWP method were expressed in the time and frequency domain. Furthermore, the calibration method of amount of accumulated charge density using mathematical deconvolution technique was described for both methods. To compare the two methods, surface charges induced by dc voltage application at the interface between sample and electrodes and volume charge in sample were observed. The electric field and electric potential distributions in sample were calculated from these results. The result of both methods shown almost same charge, electric field and electric potential distribution.