| 摘要 |
PROBLEM TO BE SOLVED: To precisely detect the concentration of a gas without using an expensive quartz vibrator as an oscillation member. SOLUTION: First and second beam members 11 and 12 contained in a gas sensor 1 oscillate first and second oscillation frequencies respectively by the predetermined drive signal given from a drive circuit 3. At this time, since the second beam member 12 having a gas response film 12a formed thereto adsorbs a gas molecule, the oscillation frequency thereof is lowered in dependence of the concentration of the gas. That is, a second oscillation frequency is lowered in dependence of the concentration of the gas. The first oscillation frequency is constant without depending on the concentration of the gas. The first and second oscillation frequencies are compared with each other and the concentration signal showing the concentration of the gas is formed in a concentration signal forming circuit 4. COPYRIGHT: (C)2007,JPO&INPIT
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