Unformatted text preview: d that this effect also occurs with many semiconductors. Certain physical characteristics are required for this. The thickness of
the small plate must be less than the dimensions of length and width. Voltages of up
to 1.5 V can be created. I A t B
VH Fig. 11.2.8: Schematic representation of the Hall effect The formula for Hall voltage is
VH = RH ⋅ I ⋅ VH
t = Hall voltage
= Hall constant
= Magnetic induction
= Plate thickness The reciprocal value in the equation of occurring Hall constants is the density of the
charge carrier in the material.
Hall sensor elements are used for the measurement of current and magnetic field or
in combination with moving magnets for angle and position. 172 © Festo Didactic GmbH & Co. KG • FP 1110 11. Physical fundamentals Magnetoresistive effect Magneto-resistive sensors operate on the principle of a change in the electrical
resistance of ferromagnetic materials under the influence of a magnetic field.
Sensors of this type consist of thin foil in strips or a meander structure. The
resistance layers consist of nickel-iron alloys (Permalloy), which are arr...
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