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Unformatted text preview: onduction instead of intrinsic conduction, because the introduced impurity atom
(impurities) decisively influence conductivity.
The change in resistance in the case of small magnetic fields is very small, due to the
fact that the sensor resistance is a square function of the magnetic field. Increased
sensitivity can be achieved through a magnetic bias in the magnetoresistor by
means of a permanent magnet. The working point of the magnetoresistor is now in
the steeper range of the squared characteristic curve thus creating a greater change
in resistance. Sensors of this type are therefore constructed from magnetoresistive
semi-conductor material in conjuction with a permanent magnet and flux-guiding
soft iron materials. Ferro-sensors Magnetoresistive sensors can be excited by means of externally approaching
permanent magnets or – in the case of magnetically biased sensors – by means of
ferromagnetic materials. The latter design is also described as a ferro-sensor. With
the approach of a ferromagnetic material, the magnetic f...
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- Spring '12