Electrical conductivity tester and methods thereof for accurately measuring time-varying and steady state conductivity using phase shift detection

A method for accurately determining the time varying conductivity and steady-state conductivity of a test material, the method comprising the steps of:

• sending a reference oscillator signal to a single probe coil means;
• magnetically coupling said reference oscillator signal and said test material with said single probe coil means to derive a modified transmission phase signal;
• comparing said reference oscillator signal to said modified transmission phase signal to derive a transmission phase signal indicative of a phase difference, said transmission phase signal being convertible to said time-varying conductivity;
• and
• averaging said transmission phase signal to determine an average phase signal, said average phase signal being convertible to said steady-state conductivity of said test material.

An electrical conductivity tester for accurately measuring the conductivity of a test material, comprising:

• an oscillator means for generating a reference oscillator signal;
• a probe means for receiving said reference oscillator signal, for magnetically coupling to said test material, and for modifying said reference oscillator signal via electromagnetic induction to derive a modified transmission phase signal;
• a phase detector means for deriving a transmission phase signal by comparing said reference oscillator signal to said modified transmission phase signal, said transmission phase signal being convertible to said conductivity;
• and
• a feedback means for filtering said transmission phase signal to derive an average transmission phase signal and for forwarding said average transmission phase signal to said phase detector means, said feedback means and said phase detector means for adjusting a phase of said reference oscillator signal so that said transmission phase signal is reduced to zero with a steady-state conductivity.

A method for accurately determining the conductivity of a test material, the method comprising the steps of:

• sending a reference oscillator signal to a probe circuit;
• magnetically coupling said reference oscillator signal and said test material to derive a modified transmission phase signal;
• comparing said reference oscillator signal to said modified transmission phase signal to derive a transmission phase signal, said transmission phase signal being convertible to said conductivity;
• filtering said transmission phase signal to derive an average transmission phase signal;
• and
• using said average transmission phase signal to adjust a phase of said reference oscillator signal so that said transmission phase signal is reduced to zero with a steady-state conductivity.