Accession Number : ADD017578

Title :   Autonulling AC Bridge using Differential and Integration Feedback.

Descriptive Note : Patent, Filed 29 Oct 91, patented 23 Nov 93,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Bey, Paul P , Jr ; Fare, Thomas L

Report Date : 23 Nov 1993

Pagination or Media Count : 9

Abstract : A self contained autonulling bridge circuit based on phase sensitive detection of an impedance to he measured is described. The system utilizes a feedback structure to control a variable impedance in order to establish the null of the bridge. The system utilizes a voltage variable impedance having both resistance and capacitance and provides the phase sensitive relationship in the control means in order to provide highly accurate measurement of an unknown test impedance. The ability to measure small changes in impedance provides particularly useful application to the area of biological sensor impedance measurement or electrochemical impedance measurement using silicon based devices.

Descriptors :   *FEEDBACK, *NULLS(AMPLITUDE), *PATENTS, *ELECTRIC BRIDGES, AUTOMATION, ACCURACY, ALTERNATING CURRENT, SENSITIVITY, INTEGRATION, SILICON, ELECTRICAL IMPEDANCE, CIRCUIT ANALYSIS, CAPACITANCE, MIXERS(ELECTRONICS), PHASE DETECTORS

Subject Categories : Electrical and Electronic Equipment
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE