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Magnetoresistive Detection Apparatus

IP.com Disclosure Number: IPCOM000084846D
Original Publication Date: 1976-Jan-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Knickmeyer, KH: AUTHOR

Abstract

This apparatus utilizes magnetoresistive sensing elements having the property of changing resistance proportionate to the magnitude and direction of an applied magnetic field. In Fig. 1, this property is employed in current measurement by sensing the field H around a conductor 10, H being proportional to the current I. Temperature dependent characteristics of the sensing material are self-compensated, by using a circuit and configuration shown in Figs. 2 and 3.

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Magnetoresistive Detection Apparatus

This apparatus utilizes magnetoresistive sensing elements having the property of changing resistance proportionate to the magnitude and direction of an applied magnetic field. In Fig. 1, this property is employed in current measurement by sensing the field H around a conductor 10, H being proportional to the current I. Temperature dependent characteristics of the sensing material are self-compensated, by using a circuit and configuration shown in Figs. 2 and
3.

Two magnetoresistive elements RS1 and RS2 form one side of a bridge configuration, as shown schematically in Fig. 2. However, they are physically positioned in space as shown in Fig. 3. Since both elements are constructed on the same substrate simultaneously, their thermal coefficients and response to a magnetic field are closely matched.

The response characteristic of these devices is such that an applied field in one direction increases resistance, while a field of the opposite direction decreases resistance. With the geometric configuration shown, the field is applied to RS1 and RS2 in opposite directions relative to the exciting current I, resulting in a change in the divider voltage proportionate to the magnitude of H, and of a polarity relative to the center of reference R1, R2 as defined by the direction of H.

R1 and R2 also have matched thermal coefficients for maximum sensor accuracy, and it is desirable to include an adjustment, as shown, to set the R1, R2 div...