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Low-power magnetometer circuit with constant current drive

  • US 4,277,751 A
  • Filed: 09/29/1978
  • Issued: 07/07/1981
  • Est. Priority Date: 09/29/1978
  • Status: Expired due to Term
First Claim
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1. In a magnetometer of the type having a toroidal core, a drive winding wound around the core so as to create a circumferential field within the core, drive means for driving the drive winding with an A.C. signal so that the field from the drive winding causes the core to saturate during at least a part of each cycle of the A.C. signal, and at least one sense winding and an associated signal processing channel responsive to signals from the sense winding for detecting a component of a surrounding magnetic field, the improvement comprising:

  • means for sensing the current flowing in the drive winding and for producing an intermediate signal representative thereof; and

    wherein the drive means includes means, responsive to the intermediate signal, for varying the frequency of the A.C. signal so as to tend to maintain a substantially constant average current flowing in the drive winding.

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