| 摘要 |
PROBLEM TO BE SOLVED: To provide a capacitive detector which can accurately detect a physical quantity with a simple circuitry. SOLUTION: An acceleration sensor CS2 includes a capacitance conversion section 20, an amplifying section 40, a detection element unit 50, and a signal control section 60. The capacitance conversion section 20 includes an operational amplifier 21, a switch 22, and a capacitor 23 and converts the change in the differential capacitance, consisting of fixed electrodes (51, 52) and a movable electrode 53, into a voltage. To the non-inversion input terminal of the operational amplifier 21, [(V1+V2)/2] is supplied as a reference voltage. The signal control section 60 supplies the voltage to be applied to the fixed electrodes (51, 52) of the detection element unit 50. The signal control section 60 is provided with a bias supply section 61. The bias supply section 61, during a test mode, applies a predetermined bias voltage to the fixed electrodes (51, 52). COPYRIGHT: (C)2009,JPO&INPIT
|
