| 摘要 |
An electrostatic capacitance detection circuit 10 comprises an AC voltage generator 11 , a first operational amplifier 14 of which non-inverting input terminal is connected to specific potential (a ground in this example), a second operational amplifier 16 that includes a voltage follower, a resistance (R 1 ) 12 connected between the AC voltage generator 11 and an inverting input terminal of the first operational amplifier 14 , a resistance (R 2 ) 13 connected between the inverting input terminal of the first operational amplifier 14 and an output terminal of the second operational amplifier 16 , and an impedance element (a capacitor) 15 connected between an output terminal of the first operational amplifier 14 and a non-inverting input terminal of the second operational amplifier 16 , and a capacitor to be detected 17 is connected between the non-inverting input terminal of the second operational amplifier 16 and specific potential. The electrostatic capacitance detection circuit 10 and the capacitor 17 are located adjacently.
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