Hall effect switching device

Claim 1

A Hall effect switching circuit including the combination of a Hall effect device having at least first, second, third and fourth contacts, whereby the first and second contacts constitute the input contacts and the third and fourth contacts constitute the output signal contacts, a source of electric power having a first terminal connected to the first contact and a second terminal connected to the second contact; a transistor having a collector electrode connected to the first terminal, an emitter electrode directly connected to the third contact, and a base electrode; a resistor connected between the base electrode and the first terminal; and a diode having one electrode directly connected to the base electrode and another electrode directly connected to the fourth contact so as to compensate for changes in the transistor characteristics due to temperature variations and to cause the transistor to switch at a low output signal from the Hall effect device and thereby render the Hall effect switching circuit less sensitive to temperature variations and fluctuations in the source of electric power, whereby the Hall effect switching circuit is operative from the output signal across the third and fourth contacts so as to be rendered further insensitive to changes in the Hall effect device characteristics due to temperature variations and to fluctuations in the source of electric power.