A potentiometer includes a magnetoresistive element made of ferromagnetic material. A device applies a magnetic field to the magnetoresistive element. An absolute value of the magnetic field applied to the magnetoresistive element is equal to or greater than a saturation magnetic field with respect to...http://www.google.fr/patents/US4835509?utm_source=gb-gplus-shareBrevet US4835509 - Noncontact potentiometer
