Patent ID: 6988409

Claim:
A dynamic quantity sensor comprising: a signal generating section for generating a detection signal having a signal level representing an applied dynamic quantity; and a signal correcting section for correcting said detection signal produced from said signal generating section in such a manner that an unapplied level of said detection signal to be obtained when said dynamic quantity is not applied is equalized to a predetermined reference level, wherein said dynamic quantity sensor has a failure mode in which an output of said signal generating section is fixed to said reference level, and said signal generating section adjusts the detection signal in such a manner that said signal correcting section generates a large correction amount sufficient for an output signal from said signal correcting section to deviate from a failure judgment unable region including said reference level in case of failure corresponding to said failure mode, wherein said signal generating section comprises a sensor element having a movable portion causing a displacement in accordance with the applied dynamic quantity, said sensor element includes first and second capacitive elements cooperatively causing a complementary capacitance change in response to the displacement of said movable portion, and a third capacitive element connected in parallel with one of said first and second capacitive elements, and said third capacitive element and said one of said first and second capacitive elements connected in parallel with said third capacitive element are connected to common terminals at both ends thereof.