Magnetoresistive effect in transition region of PN junction and its application circuits.

Four circuits are described that exploit the magnetoresistive effect in the junction region of a p-n diode. In these diodes, impurities are selectively diffused in a substrate with a low initial impurity concentration so that the width of the transition region becomes large. This increases the magnetoresistive effect within the transition region. The diodes studied have a transition region width as much as 100 times larger than in ordinary diodes. To make use of this effect a circuit that converts the change in resistance induced by a magnetic field into a voltage is proposed. When this voltage is amplified and connected to an astable multivibrator, the circuit can be used to generate either '1' or '0' pulses, corresponding to the presence or absence of a magnetic field. Circuits are presented for measuring and amplifying the magnetic effect, and generating and counting pulses.