A Linear Position Transducer Using a Magnet and Hall Effect Devices

Magnets and magnetic field sensing devices are often attractive in instrumentation because they are noncontacting, small, and independent of the media's dielectric constant. The nonlinearity of the magnetic field with distance is a problem, however. A circuit to remove this nonlinearity and also to reduce the effective temperature coefficient is described. The circuit is used in a clinical dental research laboratory to measure movements of the jaw.