| 摘要 |
PROBLEM TO BE SOLVED: To provide an acceleration sensor of static capacity detection type capable of always diagnosing the presence or the absence of breakage of the sensor, even during working, using a comparatively simple constitution. SOLUTION: The acceleration sensor comprises a square diaphragm 2 equipped with a cone 1; the base of an insulation body 3; a moveable electrode equipped on the square diaphragm and fixed electrodes X, Y, Z arranged oppositely on the base; detection circuits 4-1, 4-2, 4-3 for detecting and outputting the change of static capacitance between the moveable electrodes and the fixed electrode caused by the acceleration; a malfunction diagnosing electrode 2-1 provided on the frame surface of the square diaphragm; and a malfunction diagnosing circuit 5 (oscillation circuit 5-1, resistor R<SB>0</SB>, rectifier circuit 5-2, deciding circuit 5-3) for detecting the breakage or trouble of the acceleration sensor, where on the cone 1 opposite to the malfunction diagnostic electrode, a conductor body is provided in the vicinity area to the malfunction diagnosing electrode, and a malfunction diagnosing signal is impressed (oscillation circuit 5-1) between the malfunction diagnostic electrode and the conductor body on the cone, and the voltage of the malfunction diagnostic electrode is monitored and compared with the prescribed set voltage. COPYRIGHT: (C)2005,JPO&NCIPI
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