PURPOSE: To stabilize (demagnetize) the magnetic characteristics of a shielded core on MR head.
CONSTITUTION: An output signal from a sense current control voltage generating circuit 21 which generates a control voltage of a sense current applied to a magnetoresistance effect element in order to extract a change of resistance of the magnetoresistance effect element of a magnetoresistance effect type head as a voltage and an output signal from a demagnetization current control voltage generating circuit 22 which generates a control voltage of the demagnetization current which is an AC current of which amplitude reduces gradually are added by an adder 23. The added output signal is sent to a gm amplifier as voltage-current converting means for conversion into a current and is then applied to an MR head 11 as the magnetoresistance effect type head.
FUKUYAMA MUNEKATSU
HAYATA YUTAKA
