DC current sensors of instantaneous response using amorphous cores

A new current sensor made of three transistor core multivibrators of high frequency is presented. Three multivibrators are synchronized with external pulses so that rectangular three phase voltages may be obtained. The core flux in each multivibrator changes along the minor hysteresis loop. We have no ripple dc output voltage from the outputs of the three multivibrators in the same way as that of a mixing amplifier. The amorphous cores with excellent rectangularity are effectively used for this purpose.