Hall-type displacement sensor
Hall-type displacement sensor: its measuring principle is to keep the excitation current of the Hall element (see semiconductor magneto-sensitive element) unchanged and move it in a gradient-normal magnetic field, then the displacement is proportional to the output of Hall Potential. The larger the magnetic field gradient, the higher the sensitivity; the more uniform the gradient changes, the closer the relationship between Hall potential and displacement is linear. In Fig. 2, there are three kinds of magnetic systems that generate gradient magnetic fields: a system has a narrow linear range, and when the displacement Z=0, the Hall potential is ≠0; the b system has good linearity when Z<2 mm, when Z=0, Hall potential = 0; c system sensitivity is high, the measurement range is less than 1 mm. In the figure, N and S respectively indicate positive and negative magnetic poles. The Hall-type displacement sensor has a small inertia, high frequency response, reliable operation, and long life. Therefore, it is often used to convert various non-electric quantities into displacements and then perform measurement.