Patent ID: 7655131
Filing Date: 2010-02-02
Classification: G01N

Abstract:
1. A gas sensor comprising: a main pumping means for pumping-processing oxygen contained in a measurement gas introduced from external space, comprising solid electrolyte contacting with said external space, and an inner pumping electrode and an outer pumping electrode formed on inner and outer surfaces of said solid electrolyte; and a measuring pumping means for decomposing a predetermined gas component contained in said measurement gas after being pumping-processed by said main pumping means by the aid of a catalytic action and/or electrolysis, and pumping-processing oxygen produced by said decomposition via said outer pumping electrode of said main pumping means, wherein: a concentration of oxygen is controlled and/or the predetermined gas component is measured by allowing a pulse-shaped current to flow through said measuring pumping means; the gas sensor further comprising: a electromotive force-measuring circuit for constantly measuring the electromotive force corresponding to a difference between an amount of oxygen produced by said decomposition of said predetermined gas component and an amount of oxygen contained in a reference gas; a crest value control means for controlling a crest value of said pulse-shaped current corresponding to a difference between an the electromotive force measured by said electromotive force-measuring circuit and a comparing voltage; and a measuring circuit for at least converting the crest value of the pulse-shaped current into a concentration of said predetermined gas component.