Numerous permeabilities are defined in literature under various DC- and AC-excitation levels. In most cases, these are linearized values, which leaves the question which effective inductance is actually present during operation. The paper shows hysteresis measurements of DC biased inductances with different alternating field excitations (large-signal measurements) and the differential as well as the effective inductance derived from this. The results are compared with impedance measurements (small-signal measurements) and discussed. The measurements are performed on an MnZn toroidal core, an MnZn PM-core with air gap, and also on a powder core. In addition to investigating inductance as a function of the excitation, flux density as a function of DC current is also discussed. The article concludes with a comparison of the inductances investigated in a buck converter.
