Electricity and Magnetism > Magnetic Materials >
Magnetoresistance
DCS# 5G45.70
MAGNETORESISTIVE
SENSOR
APPARATUS
mounted AMR sensor with
connector box
202-20-B4
strong magnet
202-20-D
digital multimeter
214-01-B
camera
201
DESCRIPTION
An AMR bridge sensor from an old
computer floppy drive is used to show magnetoresistance. The
sensor consists of a Wheatstone bridge whose resistors are thin
permalloy films. Switch on the power at the connector box to
apply 1.5 V across the
bridge. In a magnetic field, the resistance of the films
change and so the output voltage changes.
These are
used as position detectors in computer drives and in read
heads.