Sprague Electric Company

Hideki Kawaji

Ravi Vig

Jacob K Higgs

Peter J Gilbert

A Hall elements and magnet assembly for use as a proximity detector includes a magnet, a pole piece mounted to one pole end of the magnet and an integrated circuit having two side-by-side Hall elements, an amplifier, interconnecting wiring providing the difference voltage between the two Hall output voltages at the input of the amplifier, and a Schmitt trigger circuit. The integrated circuit is mounted to the pole piece at the pole end of the magnet. The pole piece is a ferromagnetic member which is thinner in the center than at the periphery for achieving a highly uniform field strength across the surface of the magnet pole end toward reducing the criticality of the position of mounting of the integrated circuit in manufacturing and for extending the range of gap dimensions between a passing ferromagnetic article and the assembly for which proper detection of the passing article can be made to occur. The term 'ferromagnetic' as used herein means any material with a relative permeability greater than unity and preferably greater than 100.

Sensor having dual Hall IC, pole piece and magnet

An integrated circuit voltage regulator is of the kind having a pass transistor connected collector-to-emitter between the input V.sub.CC conductor and the regulated-voltage output conductor, a current source circuit supplying a base bias current to the pass transistor and a voltage reference and feedback regulator circuit connected between the output voltage conductor and the base of the pass transistor. A protective circuit against high voltage transients adding to V.sub.CC voltage comprises a transistor connected collector-to-emitter between the pass-transistor base and ground has a resistor paralleling the base-emitter junction, which resistor is resistively coupled to the input V.sub.CC line to shunt away the pass-transistor bias current whenever the V.sub.CC voltage level exceeds a value just under the latch-back breakdown voltage of the pass transistor. A zener diode directly connected across the DC input voltage conduction renders the regulator even more tolerant of high voltage transients.

Growing community of inventors

Andover, NH, United States of America

Hideki Kawaji