Automatic Hysteresis Measurement System with High Accuracy

A newly developed microcomputer-controlled device for automatic high-precision hysteresis measurement is reported. Microcomputer integration of dB/dt and dH/dt signals can proceed by 1) direct accumulation of the differential voltages, 2) analog integration through use of a mirror integrator, or 3) digital integration using a V - f converter. Barkhausen noise in signals leads to problems in adopting 1), and other problems attend 2), so the authors employed 3) for integration of both B and H signals. This enabled highly precise measurement of the static magnetization characteristics of single sheet samples, with a stability of 3 × 10^-6 Wb·turn/ min or more.