| 摘要 |
PROBLEM TO BE SOLVED: To eliminate changes in output if the concentration of a gas to be measured is constant regardless of changes in temperature by forming a resistance system with the temperature characteristic of a resistance value opposite to the output characteristic of a gas sensor to build up a closed circuit with the resistance system and the gas sensor. SOLUTION: A sensor body 2 comprising an insulating material has a hole 4, provided in the bottom part, closed by a diaphragm 6. The sensor body 2 holds sulfuric acid therein as electrolyte 12 and a detection pole 8 is formed on the side of the electrolyte on the diaphragm 6. The diaphragm 6 herein used is a porous gas permeable film and the detection electrode 8 is a noble metal film made of gold, platinum or the like. The potential of the detection pole 8 is kept constant by a potentiostat 20 with the potential of a control electrode 16 as reference and the concentration of specified components in the gas to be inspected is detected by a current between a counter pole 14 and the detection pole 8. In a detection circuit, a resistance 34 is connected in series to a thermistor 32 with the temperature characteristic thereof opposite to that of a current output of the sensor and a resistance 36 is connected in parallel to the thermistor 32 to build a resistance system. |
