Abstract: This invention relates to an acceleration sensor device suitable for self-checking while a vehicle is being driven and a self-checking circuit therefor. An acceleration sensor device for self-checking while driving is comprised of a planar vibrator having a piezoelectric area and a non-piezoelectric area and a plurality of first electrodes provided on an upper face of the piezoelectric area of the planar vibrator. At least one second electrode is provided on an upper face of the non-piezoelectric area of the planar vibrator, and a third electrode is provided on the lower face of the planar vibrator. Inputs to the self-checking circuits provide an output that represents the operating state of the acceleration sensor.

Abstract: This invention relates to an acceleration sensor having less output drift due to temperature change and noise due to external induction which includes a piezoelectric device formed of a piezoelectric member having one or more electrodes provided on each of sides thereof and a lining member of low linear expansion coefficient adhered to one side thereof. A low linear expansion coefficient circuit substrate is provided having the piezoelectric device adhered to one side thereof and having a signal processing electronic circuit formed on the other side thereof. A cabinet having three layers, including an internal conductive resin layer, an adiabatic resin layer, and an external conductive metal layer, completely enclose the piezoelectric device and the circuit substrate.