ACCELERATION SENSOR

PROBLEM TO BE SOLVED: To provide an acceleration sensor which simplifies a signal to be input to an acceleration sensor for conducting self diagnosis. SOLUTION: The acceleration sensor includes a support and a displacement body 22 that is supported in freely displaceable manner with respect to the support, wherein the support is provided with a first fixed electrode 31 and a second fixed electrode 32, and the displacement body 22 is provided with a first movable electrode 41 and a second movable electrode 42; the acceleration is output with the difference in capacitances C1-C2 between the capacitance C1 of the first fixed electrode 31 and the first movable electrode 41, and the capacitance C2 of the second fixed electrode 32 and the second movable electrode 42, as a detection output Vout of acceleration; and when a self-diagnosis signal STin is input, self-diagnosis processing is started, and the phase in the self-diagnosis processing is synchronized with the waveform of the self-diagnosis signal STin, and then a phase 1 for applying voltage between the first fixed electrode 31 and the first movable electrode 41 and a phase 2 for applying voltage between the second fixed electrode 32 and the second movable electrode 42 are sequentially shifted automatically. COPYRIGHT: (C)2011,JPO&INPIT