MONITORING OF GAS SENSORS

摘要

a monitor is disclosed for monitoring an atmosphere for the presence of a target gas, the monitor comprising: 1. an electrochemical gas sensor (11) having a working (sensing) electrode (11a) and a counter electrode (11b), the sensor providing a current between the electrodes that is indicative of the amount of target gas in the atmosphere; 2. an operational amplifier (12) connected between the sensor electrodes to generate an output signal according to the current flowing between the terminals, whereby the output signal is indicative of the amount of target gas in the atmosphere, 3. a detector (20,22) for detecting when the current flowing between the sensor electrodes exceeds a predetermined threshold; and 4. a circuit (24) that restricts the potential difference between the sensor electrodes when the current between the terminals exceeds the predetermined threshold by supplying additional current to or removing current from the working sensor electrode (11a).