| 摘要 |
PROBLEM TO BE SOLVED: To provide a combustible gas concentration measuring instrument, capable of detecting the concentration of combustible gas from low concentration up to high concentration impossible of combustion. SOLUTION: In a hydrogen concentration measuring instrument using the catalytic combustion type gas sensor 1, constituted by forming an oxidizing catalyst layer subjecting combustible gas to oxidative reaction to generate heat on the surface of a heater generating heat by Joule heat due to energization, so as to form heat conduction relation, while keeping electric insulation, the catalytic combustion type gas sensor 1 and a thermally conductive type gas sensor 5 are connected to a bridge circuit, so as to divide the voltage of a constant voltage keeping circuit proportionally and the concentration of hydrogen gas is detected, on the basis of bridge output and the current flowing to the sensors 1 and 5.
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