GAS SENSOR OPERATING USING THERMAL-CONDUCTIVITY MEASUREMENTS

摘要

The invention concerns a gas sensor for the determination of the concentration, or change in concentration, of gaseous impurities in gases by means of thermal-conductivity measurements. The sensor includes a PTC resistor (1) with a high temperature coefficient and a processing circuit which determines, from the change in resistance of the PTC resistor (1) caused by the impurity, the concentration or change in concentration of the impurity. The sensor preferably also includes an additional PTC resistor (2) as a reference resistor, plus a processing circuit which determines, from the difference between the resistances of the PTC resistors (1 and 2) caused by the impurity, the concentration or change in concentration of the impurity. The invention also concerns a method for the determination, using thermal-conductivity measurements, of the concentration or change in concentration of gaseous impurities in gases with the sensors described.