Contactless measurement of electrical resistivity by eddy current methods: discussion and a new technique

Abstract

The eddy current decay and the AC (steady-state) methods of contactless electrical resistivity measurement are compared in terms of linear system theory. Theoretically both methods are equivalent, but from experimental considerations the AC method is preferable for all but extremely low resistivity values. A simplified version of the AC method based on a phase angle measurement is described. One single phase angle measurement suffices to determine the absolute value of resistivity.