Resonance Analysis of a Permeance Meter Using a Figure-of-Eight Coil

We derived an equivalent circuit for a figure-8 coil type permeance meter in order to analyze its LC resonance characteristics. The equivalent circuit for the pickup coils was derived by using the same analytical techniques as for thin-film inductors. The driving sheets and twisted lead wires were modeled according to the theory of distributed constant networks. We made a permeance meter, measured the frequency characteristics of the impedance for the coils, and confirmed the validity of the equivalent circuit. After describing the above steps, we discuss the LC resonance caused by the stray capacitance between the pickup coils and the driving sheets.