SEISMIC SENSOR AND SEISMOSCOPE USING THE SAME

摘要

PURPOSE:To house a seismic sensor which enables the cutting of a city gas being supplied when an earth quake occurs into a gas meter, a gas emergency breaker, a gas consuming device or the like by miniaturizing it without variations in characteristic. CONSTITUTION:A spherical pendulum comprising a conducting monocrystalline silicon hangs with a support part 71 and an electrode 73 is arranged on a virtually spherical surface having he same center in a natural condition as the center of the pendulum. Those corresponding to each other of three pairs of the electrodes 73a are connected in common to detect capacity between the pendulum and the electrodes. A level discrimination is performed through a lowpass filter for filtering seismic waves alone. This achieves a prevention of variations in characteristic of each product, a miniaturization of a construction and higher sensitivity to eliminate restriction of mounting attitude thereby enabling selective detection of all vibrations such as earth quake in a three-dimensional direction.