| 摘要 |
PROBLEM TO BE SOLVED: To provide a capacity type physical sensor capable of inhibiting influence from frequency noise and obtaining a sensor characteristic of high quality. SOLUTION: The substrate A, in which the sensor element 10 is equipped, and the noninverting input terminal of the OP AMP 21a are connected, and they are fixed with the same voltage by supplying the common voltage from the midpoint voltage of the supply circuit 21d. Thereby, the impedance matching of the noninverting input terminal and the inverting input terminal of the OP AMP 21a to the power source is made possible, therefore the noise superposed on the power supply line can be extremely reduced by the noise reduction property determined by the CMRR property of the OP AMP 21a. Consequently, the capacity type acceleration sensor can be obtained with a sensor property of high quality by reducing the influence from the frequency noise. COPYRIGHT: (C)2007,JPO&INPIT
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