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 prop agation (PWP) methods for measuring the space charge distributions in solid dielectrics are summarized. The relationship between the charge distributi on 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. Further more, the calibration method of the amount of accumulated charge density us ing deconvolution techniques is described for both methods. To compare thes e two methods, PMMA samples with and without space charge are measured usin g both methods. In addition, the electric field and electric potential dist ributions are calculated and discussed. The experimental results obtained u sing both methods are almost the same.