CAPACITANCE-VOLTAGE CONVERSION DEVICE AND CONVERSION METHOD

摘要

PROBLEM TO BE SOLVED: To accurately convert capacitance into voltage by utilizing an operational amplifier in an imaginary short state. SOLUTION: The operational amplifier 21 has a reversing input terminal (+), a nonreversing input terminal (-), and an output terminal 22, the reversing input terminal and the nonreversing terminal are connected with a feedback resistance 23, and an imaginary short state is kept between the output terminal 22 and the reversing input terminal. One end of a signal wire 25 is connected to the reversing input terminal and the other end of the signal wire 25 can be connected to a capacitance element 26. A shielding wire 27 connected to the nonreversing input terminal envelopes at least a part of the signal wire 25. When AC voltage is applied to the nonreversing input terminal, AC voltage corresponding to the capacitance element 26 is outputted from the output terminal 22 of the operational amplifier 21.