Time varying electrical conductivity tester using frequency disc

Details Time varying electrical conductivity tester using frequency disc Time varying electrical conductivity tester using frequency disc

1994-03-28

1996-02-27

Snow, Walter E.

Electricity: measuring and testing

Magnetic

With means to create magnetic field to test material

324655, 324719, G01N 2772, G01R 3312, G01R 3126, G01R 2728

Patent

active

054951704

ABSTRACT:
An electrical conductivity tester accurately measures the time-varying electrical conductivity .sigma.(t) and steady-state electrical conductivity .sigma..sub.ss, of a test material. In a first embodiment, the transmission phase of a probe circuit is monitored to determine the conductivity of a test material. In the first embodiment, an oscillator circuit generates a reference oscillator signal. A probe circuit receives the reference oscillator signal, magnetically couples to the test material, and modifies the reference oscillator signal via electromagnetic induction to derive a modified transmission phase signal. Finally, a phase detector circuit derives a transmission phase signal by combining the reference oscillator signal and the modified transmission phase signal, the transmission phase signal being directly convertible to the conductivity. In a second embodiment, an amplifier is connected to the probe circuit to form an oscillator circuit. The oscillator circuit generates an oscillator signal in response to the magnetic coupling of the probe circuit with the test material. A frequency discriminator generates a frequency signal from the oscillator signal, the frequency signal being convertible to the conductivity.

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