GAS SENSOR, CONTROL METHOD FOR GAS SENSOR, GAS CONCENTRATION CONTROLLER AND CONTROL METHOD FOR GAS CONCENTRATION

摘要

PROBLEM TO BE SOLVED: To obtain a gas sensor in which the oscillation phenomenon of the feedback control system of a control voltage to an oxygen pump is eliminated effectively when, e.g. the oxygen pump is used. SOLUTION: A gas sensor is constituted in such a way that a voltage across an inside pump electrode 24a and a reference electrode 26 is measured so as to find the difference between a measured voltage and a reference voltage and that a pump voltage Vp is controlled by the differnce voltage. Concretely, a comparison amplifier 32 is installed in such a way that the voltage across both ends of the reference electrode 26 and the inside pump electrode 24a is compared with a reference voltage Vb and that their difference is amplified at a prescribed gain so as to be output. The comparison amplifier is wired, connected and constituted in such a way that an output voltage (a difference voltage) from the comparison amplifier 23 is used as the pump voltage Vp to an oxygen pump 22 so as to be applied across the inside pump electrode 24a and an outside pump electrode 24b. In addition, the inside pump electrode 24a is grounded.