Skin depth and complex magnetic susceptibility: An experimental alternative approach

Abstract

A different approach in the discussion of the skin effect in a metal cylinder, is described, where the presence of eddy currents is assumed to be a consequence of an equivalent static magnetization. A low-cost, easy to build mutual inductance bridge is used to measure the equivalent magnetic susceptibility—a function of the skin depth. The use of a lock-in amplifier as a null detector clearly shows the concept of complex magnetic susceptibility. The electrical resistivity of a copper rod is measured as an application thereof. The results are shown and compared to theory achieving excellent agreement.