Ferromagnetic article detector with dual Hall-sensors

摘要

Two identical integrated circuit (IC) chips are mounted at a pole of a magnet. Each IC chip includes a Hall-element followed by an amplifier. A comparator is connected to the outputs of the IC chips to produce a voltage that is directly related to the difference between the magnetic field strengths at the two IC chips that may be due to a ferromagnetic article that is closer to one IC chip than the other.