Gas sensor, method for controlling gas sensor, gas concentration controller and method for controlling gas concentration

摘要

A system is constructed such that a voltage between an inner pumping electrode (24a) and a reference electrode (26) is measured to determine a difference between a measured voltage and a reference voltage so that a pumping voltage (Vp) is controlled by using the differential voltage. Specifically, a comparative amplifier (32) is provided for comparing the reference voltage (Vb) with the terminal voltage between the reference electrode (26) and the inner pumping electrode (24a), and amplifying the difference therebetween with a predetermined gain to make an output. The system is wired and connected such that the output voltage (differential voltage) from the comparative amplifier (32) is applied, as the pumping voltage (Vp) supplied to an oxygen pump (22), between the inner pumping electrode (24a) and an outer pumping electrode (24b). The inner pumping electrode (24a) is grounded. Accordingly, for example, when the oxygen pump is used, it is possible to effectively avoid the oscillation phenomenon in the feedback control system for the control voltage for the oxygen pump. <IMAGE>