Patent ID: 6927568

Claim:
A rotational-rate sensor, comprising: a detecting element; a circuit portion for controlling the drive of the detecting element at the resonance frequency thereof in the direction where the detecting element is driven, and outputting, through a low-pass filter, a signal according to a rotational rate that is obtained from the detecting element; an airtight container which houses the detecting element and the circuit portion, the airtight container being made of ceramics or resin and including wiring for transmitting an input and output signal to the circuit portion; and an elastic body which is disposed between the airtight container and an attached body to which the rotational-rate sensor is attached, wherein: the synthetic resonance-frequency of a machine system which is formed at least by the detecting element, the circuit portion, the airtight container and the elastic body, and the frequency of an applied rotational rate which corresponds to the difference between the resonance frequency in the direction where the detecting element is driven and the resonance frequency of the detecting element in the direction where the detecting element detects a rotational rate, are each lower than each of the resonance frequency in the direction where the detecting element is driven and the resonance frequency in the direction where the detecting element detects a rotational rate; and the cut-off frequency of the low-pass filter in the circuit portion is lower than each of the synthetic resonance-frequency and the frequency of the applied rotational rate.