| abstract |
Disclosed is a gas sensor (10A) for controlling anconcentration of oxygen and/or measuring NOx by allowing ancurrent to flow through an ion-conductive member fornconducting oxygen ion, by the aid of a current supplyncircuit (14), wherein the current, which is outputted fromnthe current supply circuit (14), has a pulse waveformn(current signal) (Sif) having a constant crest value, andnthe current supply circuit (14) comprises a rectangularnwave-generating circuit (76) for controlling a frequency ofnthe current signal (Sif) on the basis of an electromotivenforce (V2) generated in the ion-conductive member to whichnthe current signal (Sif) is supplied. Accordingly, it isnpossible to highly accurately measure the predetermined gasncomponent while scarcely being affected by the electricnnoise or the like. |