C-MOS Multivibrator Type Micro Magnetic Sensor Using Amorphous Wire Magneto-Impedance (MI) Head

Abstract

A new sensitive and low power consumption micro magnetic sensor is presented using an amorphous wire MI head installed in a C-MOS multivibrator. The impedance in the MI head is sensitively changed with more than 80%/Oe due to a sharp current magnetization during a transient period in the C-MOS inverter. The sensor circuit operates with a high stability due to a current source like operation in the source line and the independence of the field detection sensitively on the oscillation frequency of the multivibrator. A power consumption is less than 1mW in the C-MOS multivibrator having a 250kHz oscillation frequency.