STP526

    An Integrating Type of Electronic Hysteresigraph

    Published: Jan 1973


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    Abstract

    An electronic hysteresigraph, which integrates without recourse to electromechanical means and is free of drift, has been developed. In operation, a search coil surrounds the magnetic specimen to be tested, and the specimen is then subjected to a change in externally applied magnetic field strength. The time integral of the potential induced in the search coil is a measure of the magnetic flux change in the specimen. The induced potential is applied to a solid-state voltage-to-frequency converter which produces a series of output pulses, the number of which is proportional to ∫e dt. These pulses are summed on a digital counter to give a measure of the flux change. A digital-to-analog converter then provides a d-c output which drives the Y-axis of an X-Y recorder.

    A signal proportional to the applied magnetic field strength is simultaneously fed to the X-axis of the recorder, and a continuous B versus H plot is obtained. This is a real-time mode as the response of the various measuring elements is practically instantaneous.

    In considering the integrator, it is interesting to note that absolute accuracy traceability in calibrating the voltage-to-frequency converter is referred directly to the volt, as represented by the standard cell, and to the second, as represented by a crystal-controlled time base. This is in contrast to the generally used secondary standards of mutual inductance and current shunt millivolt drop.

    Keywords:

    hysteresis, magnetic materials, recording instruments, galvanometers, flux (rate), conversion, photoelectric materials, coils


    Author Information:

    DeMott, EG
    Crucible Steel Company of America, Elizabethtown, Ky.


    Paper ID: STP36855S

    Committee/Subcommittee: A06.01

    DOI: 10.1520/STP36855S


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