| 摘要 |
PURPOSE: To form a sensor easy to handle and high in accuracy by using a coil wherein a catalyst such as Pt black-Al2 O3 , or the like is electrodeposited on an Fe-Pd alloy wire large in specific resistance and temp. coefficient. CONSTITUTION: A coil obtained by electrodepositing a catalyst such as Pt black- Al2 O3 , or PdO-Al2 O3 , or an Fe-Pd alloy wire of 10-40μm is used in the activation part S and compensation part D of a circuit and bridge resistorsγ1 -γ3 are arranged to the opposite side thereof in series and a sensitive meter V0 and a bridge power supply Vi are together provided to form a low concn. alcohol sensor. When bridge voltage of 6V is applied to this sensor, sensitivity of 11mV is obtained in the case of 100ppm of H3 OH and sensitivity of 56mV is obtained in the case of 500ppm of CH3 OH and good sensitivity is obtained even in the case of C2 H5 OH. At a time of measurement, the temp. of the sensor is set to 140-16 deg.C in the case of CH3 OH and set to 150-200 deg.C in the case of C2 H5 OH. When the Fe-Pd alloy wire is used in the activation part S and the compensation part D, the sensor good in sensitivity and excellent in uniformity and mass productivity is obtained.
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