A hysteresigraph for permanent magnet materials

The article describes a simple apparatus which may be constructed in the laboratory to measure and record the demagnetization curve (or the full hysteresis loop) of permanent magnet materials. The applied field H is measured by a Hall probe driven from a constant current source. The magnetic induction B is measured by an air-flux compensated search coil and integrating circuit. The ( B, H ) curve is plotted directly on an XY recorder.