Patent ID: 7533582

Claim:
An acceleration detector detecting an X-axis component of an acceleration applied in an XYZ three-dimensional coordinate system, the detector comprising: a displacement substrate extending along an XY-plane in the coordinate system, a detector casing accommodating the displacement substrate, a periphery of the displacement substrate being supported by the detector casing so that the displacement substrate is caused to be displaced in the detector casing when an acceleration is applied, displacement electrodes located on a surface of the displacement substrate, fixed electrodes fixed to the detector casing and opposing to the displacement electrodes, respectively, so that capacitance elements are formed, each of said capacitance elements is constituted by a displacement electrode and an opposing fixed electrode, a detecting circuit to detect the X-axis component based on a capacitance of a capacitance element among said capacitance elements, and a testing circuit to exert a coulomb force between a displacement electrode and a fixed electrode constituting one of said capacitance elements so that a state equivalent to a state where an X-axis component of acceleration is applied can be created without actually applying an acceleration.