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Saturble core device with DC component elimination for measuring an external magnetic field

  • US 4,972,146 A
  • Filed: 04/21/1989
  • Issued: 11/20/1990
  • Est. Priority Date: 11/06/1986
  • Status: Expired due to Fees
First Claim
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1. Device for measuring an external magnetic field comprisingtwo cores consisting of a material having high permeability;

  • two magnetizing coils connected in series one to another and to a source of alternating current and each being coupled to an assigned core to magnetize the same;

    two measuring coils connected in series one to another and each being coupled to an assigned core and being exposed to the external magnetic field to be measured; and

    integrating device connected at its input with the measuring coils to integrate a measurement voltage (Ua) induced in the measuring coils due to the combined alternating magnetic field in the cores generated by the magnetizing coils, and the external magnetic field to be measured, and producing an integrated voltage (Uai) at its output;

    separating means having an input connected to the output of the integrating device for separating a direct current component (U=) from the integrated voltage (Uai);

    a subtracting device connected with the output of the integrating device and the output of the separating means to subtract the direct current component (U=) from the integrated voltage (Uai) and to produce an output signal (Ux) devoid of the direct current component;

    a regulating device connected to the output of the subtracting device, an output of the regulating device being connected with a coil for compensating a steady field in said cores; and

    another output of the regulating device being connected to a device for controlling the selection of sampling time points (tm) at the peak values of the measurement voltage (Ua).

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