Electrical resistance measurement
AssigneeImperial Chemical Industries PLC
InventorJoshua C. Quayle
Life of this patent
Estimating the term…
Abstract
Monitoring the change of resistance of a test element by passing a current through the element in series with a standard element, comparing the voltage across the test element with a standard voltage to produce a signal dependent on the difference between the voltages, feeding said signal to a current modifier so as to vary the current to maintain the voltage across the test element constant, and monitoring the change in voltage across the standard element.
Claims9
A method of monitoring a resistance modifying parameter of a test element by passing a current through said test element and a reference element connected in series therewith, maintaining the resistance modifying parameter of said reference element constant, varying said current to maintain the potential difference across the test element constant, and monitoring the potential difference across the reference element, characterised by varying the current by comparing the potential difference across the test element with a standard potential difference, producing a signal dependent on the difference between said potential differences, feeding said signal to a current modifier in series with the test and reference elements, whereby said current is varied in response to said signal to maintain the potential difference across the test element at a preset value.
Apparatus for monitoring a resistance modifying parameter of a test element comprising a test element connected in series with a reference element in which said resistance modifying parameter is maintained constant, means to pass a current through said elements, means to vary said current, means to compare the potential difference across the test element with a standard potential difference, and means to monitor the potential difference across the reference element, characterised in that the means to compare the potential difference across the test element with a standard potential difference includes means to produce a signal dependent on the difference between the potential difference across the test element and the standard potential difference, and said means to vary the current is operated by said signal to vary said current to maintain the potential difference across the test element at a preset value.
Dependencies are inferred from the claim text.