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Title: Automatic control and detector for three-terminal resistance measurement

Abstract

A device is provided for automatic control and detection in a three-terminal resistance measuring instrument. The invention is useful for the rapid measurement of the resistivity of various bulk material with a three-terminal electrode system. The device maintains the current through the sample at a fixed level while measuring the voltage across the sample to detect the sample resistance. The three-electrode system contacts the bulk material and the current through the sample is held constant by means of a control circuit connected to a first of the three electrodes and works in conjunction with a feedback controlled amplifier to null the voltage between the first electrode and a second electrode connected to the controlled amplifier output. An A.C. oscillator provides a source of sinusoidal reference voltage of the frequency at which the measurement is to be executed. Synchronous reference pulses for synchronous detectors in the control circuit and an output detector circuit are provided by a synchronous pulse generator. The output of the controlled amplifier circuit is sampled by an output detector circuit to develop at an output terminal thereof a D.C. voltage which is proportional to the sample resistance R. The sample resistance is that segment of the samplemore » between the area of the first electrode and the third electrode, which is connected to ground potential.« less

Inventors:
 [1]
  1. Morgantown, WV
Issue Date:
Research Org.:
MERC
OSTI Identifier:
862685
Patent Number(s):
3988669
Application Number:
05/605,370
Assignee:
United States of America as represented by United States Energy (Washington, DC)
Patent Classifications (CPCs):
G - PHYSICS G01 - MEASURING G01V - GEOPHYSICS
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
automatic; control; detector; three-terminal; resistance; measurement; device; provided; detection; measuring; instrument; useful; rapid; resistivity; various; bulk; material; electrode; maintains; current; sample; fixed; level; voltage; detect; three-electrode; contacts; held; constant; means; circuit; connected; electrodes; conjunction; feedback; controlled; amplifier; output; oscillator; provides; source; sinusoidal; reference; frequency; executed; synchronous; pulses; detectors; pulse; generator; sampled; terminal; proportional; segment; third; ground; potential; automatic control; reference pulse; ground potential; detector circuit; circuit connected; output terminal; measuring instrument; control circuit; pulse generator; feedback control; reference voltage; amplifier output; amplifier circuit; bulk material; resistance measuring; fixed level; rapid measurement; resistance measurement; oscillator provides; device maintains; held constant; three-terminal resistance; /324/

Citation Formats

Fasching, George E. Automatic control and detector for three-terminal resistance measurement. United States: N. p., 1976. Web.
Fasching, George E. Automatic control and detector for three-terminal resistance measurement. United States.
Fasching, George E. Tue . "Automatic control and detector for three-terminal resistance measurement". United States. https://www.osti.gov/servlets/purl/862685.
@article{osti_862685,
title = {Automatic control and detector for three-terminal resistance measurement},
author = {Fasching, George E},
abstractNote = {A device is provided for automatic control and detection in a three-terminal resistance measuring instrument. The invention is useful for the rapid measurement of the resistivity of various bulk material with a three-terminal electrode system. The device maintains the current through the sample at a fixed level while measuring the voltage across the sample to detect the sample resistance. The three-electrode system contacts the bulk material and the current through the sample is held constant by means of a control circuit connected to a first of the three electrodes and works in conjunction with a feedback controlled amplifier to null the voltage between the first electrode and a second electrode connected to the controlled amplifier output. An A.C. oscillator provides a source of sinusoidal reference voltage of the frequency at which the measurement is to be executed. Synchronous reference pulses for synchronous detectors in the control circuit and an output detector circuit are provided by a synchronous pulse generator. The output of the controlled amplifier circuit is sampled by an output detector circuit to develop at an output terminal thereof a D.C. voltage which is proportional to the sample resistance R. The sample resistance is that segment of the sample between the area of the first electrode and the third electrode, which is connected to ground potential.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1976},
month = {10}
}

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