Hysteresis Loop Tracer

The magnetic field has been obtained with an ac mains driven multilayered solenoid. This magnetic field has been calibrated with a Hall Probe for uniformity and correspondence with the magnetic field calculated through ac current passing in the solonoid. A small resistance in series with the solenoid serves the purpose of taking a signal e corresponding to H. The signal e (corresponding to dJ/dt) 1 2 is taken from the pick up coil placed at the centre of the solenoid and contains the sample. It is integrated and corrected for phase. This signal is then subtracted from the reference signal e and amplified to give the signal corresponding to J. The e signal is also subtracted 1 1 from 3e in correct ratio (to account for demagnetisation and area ratio) and amplified to give signal corresponding to H. E is also  passed through the differentiator for getting signal corresponding to d J/dt which is used for phase 2 identification.