Space charge measurements on multi-dielectrics by means of the pulsed electroacoustic method

The pulsed electroacoustic (PEA) method is now widely accepted as one of the most simple and effective techniques for the measurement of the dynamic space charge distribution in solid dielectrics. Recently, the PEA method has been applied also to laminar test objects composed of two or more layers of different dielectrics (multi-dielectrics). However, when a multi-dielectric is tested by means of the PEA method, the different acoustic and electric properties of the materials affect the detected space charge signal. In this paper, the principle of the PEA technique is reviewed in case the test object is a multi-dielectric. The generation, transmission and reflection of electrically-induced acoustic waves are described. Based on the proposed approach, results of PEA measurements performed on various kinds of multi-dielectrics are presented and discussed.