Patent ID: 6277255
Filing Date: 2001-08-21
Classification: G01N

Abstract:
An electromechanical cell sensing circuit comprising:an electromechanical cell having a working electrode, a counter electrode, a reference electrode and an electrolyte, said reference electrode sensing a potential at a position in said electrolyte when an introduction of gas to be analysed into said electromechanical cell provides a current flow between said counter electrode and said working electrode;a power supply having a pair of voltage rails at different potentials;biasing means for offsetting a potential of said counter electrode from one of said voltage rails;an amplifier to monitor a voltage difference between said reference electrode and said working electrode, and to apply a feedback current to said working electrode through a feedback loop to maintain said working electrode at substantially a same potential as said reference electrode; anda measurement circuit to monitor said feedback current as a measure of said current between said working electrode and said counter electrode.