Patent ID: 7004027

Claim:
An acceleration measuring device comprising: an electrostatic-capacity-type acceleration sensor including a first capacitance detector having plural pairs of moving electrodes and fixed electrodes, which are arranged to face each other on a substrate surface such that facing areas therebetween are varied in response to an input acceleration, and a second capacitance detector having plural pairs of moving electrodes and fixed electrodes, which are arranged to face each other on the substrate surface such that facing areas therebetween are varied in response to the input acceleration and are set to be larger than the facing areas between the moving electrodes and the fixed electrodes of the first capacitance detector when the input acceleration is zero; a first detection circuit for producing a first acceleration signal in response to capacitance variation occurring between the moving electrodes and the fixed electrodes of the first capacitance detector; a second detection circuit for producing a second acceleration signal in response to capacitance variation occurring between the moving electrodes and the fixed electrodes of the second capacitance detector; and a selector for selectively outputting the first acceleration signal as long as the first acceleration signal does not exceed a threshold level determined in advance and for selectively outputting the second acceleration signal when the first acceleration signal exceeds the threshold level.