GAS SENSOR

摘要

A gas sensor capable of reversibly and continuously measuring the concentration of a catalyst poison gas such as CO without specially needing a recovering means such as a heater, and measuring a catalyst poison gas concentration without being affected by an H2O concentration. The electrical circuit (15) of the gas sensor has an ac power supply (19) for applying an ac voltage to between both electrodes (3), (5), an ac voltmeter (21) for measuring an ac voltage (ac effective voltage V) between the both electrodes (3), (5), and an ac ammeter (23) for measuring a current (ac effective current I) running between the both electrodes (3), (5). An impedance is determined from an ac effective voltage V and an ac effective current I generated when an ac voltage is applied to the both electrodes (3), (5). Since this impedance corresponds to a catalyst poison gas concentration, a catalyst poison gas concentration can be determined from an impedance by using a map showing the relation between an impedance and a catalyst poison gas concentration.