Georgia Tech Research Corporation

David R Hertling

Robert K Feeney

Ajeet Rohatgi

David W Hughes

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.

Electrical conductivity tester and methods thereof for accurately

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.

Time varying electrical conductivity tester using frequency

Method for altering an electrical characteristic of a circuit having at least one active semiconductor device involves applying at least one pulse--a voltage pulse, a current pulse, an energy pulse, or a power pulse and so forth--across the active semiconductor device, the pulse having sufficient amplitude of one or more of its electrical parameters and time duration to alter the electrical characteristics of the device, and thereby, the electrical characteristic of the circuit. The pulse is applied across the junction by applying it to at least one terminal or electrode which is contacted to semiconductor material disposed within the device. In a preferred embodiment of the inventive method, the amplitudes of the electrical parameters and the time duration of the at least one pulse should be high enough to ensure that dendrites or filaments of material from the electrode are formed in the semiconductor material of the active semiconductor device but whose dendrites or filaments are not of a geometry to cause a short cricuit to be formed between any pair of electrodes of the active semiconductor device.

Growing community of inventors

Stone Mountain, GA, United States of America

David R Hertling