PURPOSE: To extend the life of a head by providing a current adjusting circuit, which adjusts the output current of a constant current source, in the output end of a magneto-resistance effect element to prevent the disconnection of a magneto-resistance film due to wear of the head.
CONSTITUTION: The output of a sensor 10 is led to a regenerative amplifier 13 through a lead wire 11, and the output voltage obtained through the regenerative amplifier 13 is fed back to a preamplifier 15 in a voltage control circuit 14. The output voltage amplified by the preamplifier 15 is connected to the base of a transistor TR16, and the output level of the base is changed to change the output level of the emitter of the TR16. Thus, even if a resistance value R1 of the sensor 10 is changed, the current adjusting circuit 12A keeps the current density of said sensor 10 constant without the influence of this change.
OOURA MASAKI
KARAKAMA YOSHIAKI
ARAI SHINICHI
KOSUGE MINORU
KAMO YOSHIHISA
SHIGEMATA KAZUHIRO
TSUCHIYA HIROSHI
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