Electrical Conductivity Tester And Methods Thereof For Accurately Measuring Time-varying And Steady State Conductivity Using Phase Shift Detection
Feeney, Robert K.
Hertling, David R.
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An electrical conductivity tester accurately measures the time-varying electrical conductivity σ(t) and steady-state electrical conductivity σ 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.
- Georgia Tech Patents