| 摘要 |
PURPOSE:To decrease the deposition annihilation cycles of an active metal and to maintain the accuracy of measurement for a long period of time by impressing a constant current power source to a gas sensor only when the resistance value of the electrode on the side of the gas to be detected is changed by an active gas, thereby executing constant current electrolysis. CONSTITUTION:A signal amplifier circuit 10 is connected between a pair of terminals 8 and 9 of the electrode 5 on the side of the gas to be detected of the gas sensor 4 on which the active metal is deposited by evaporation. The active metal reacts and the resistance value of the electrode 5 increases when the active gas G is formed by the generation of electric discharge. Since the output of an operational amplifier 11 increases as well, a transistor 15 turns on and a relay 16 is energized to close a make and break switch 2. The voltage of a constant current power source 1 is consequently impressed between the electrodes 5 and 6 of the sensor 4. The constant current electrolysis of the sensor 4 is thus executed and the amt. of the active gas is measured. |
