Saturble core device with DC component elimination for measuring an external magnetic field
First Claim
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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Accused Products
Abstract
A device for measuring a magnetic field which is constant or varies over time, includes at least one core (3, 4) consisting of a material having high permeability, a coil (5, 6) for the magnetization of this core via an alternating current source (I) connected to the coil, and at least one measuring coil (7, 8) in which a voltage is induced corresponding to the magnetic field resulting in the coil produced by means of the applied alternating current and the external magnetic field to be measured. In order to measure very small magnetic fields and relative changes in the fields, an integrating device (9) connected with the measuring coil (7, 8), an arrangement for subtracting the d.c. voltage component from the alternating voltage component of the measurement voltage (Uai) and a device for detecting the peak values of consecutive half-waves of the output signal (Ux) of the subtracting arrangement (13, 10) are provided.
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Citations
7 Claims
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1. Device for measuring an external magnetic field comprising
two 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). - View Dependent Claims (2)
- 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;
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3. Device for measuring an external magnetic field, comprising
at least one core consisting of a material having high permeability; - a magnetizing coil connected to a source of alternating current and being coupled to said core to magnetize the same;
a measuring coil coupled to said core and being exposed to the external magnetic field to be measured;
an integrating device connected at its input with the measuring coil to integrate a voltage (Ua) induced in the measuring coil due to the combined alternating magnetic field in the core generated by the magnetizing coil, 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 connected to the subtracting device; and
a device for detecting the maximum values of consecutive half-waves of the output signal (Ux). - View Dependent Claims (4, 5, 6, 7)
- a magnetizing coil connected to a source of alternating current and being coupled to said core to magnetize the same;
Specification