| 摘要 |
PROBLEM TO BE SOLVED: To provide a seismoscope which does not have mechanical contact friction and has a small dispersion of articles in detection sensitivity by magneti cally detecting the movements of the magnetic body without contacts. SOLUTION: When there are no vibrations, a hard ball 17 rests at the center of a housing 19 and a magnetic flux 25 from a permanent magnet 22 toward the hard ball 17 vertically acts upon the hard ball 17 with a constant force and the resistance value of a magnetoresistive element 23 maintains a constant value. In the occasion of an earthquake, the hard ball 17 moves in the housing 19 to a hard-ball position 24, and the magnetic flux 25 which acts from the permanent magnet 22 upon the hard ball 17 is bent. Therefore, the strength of the magnetic force which acts on the magnetoresistive element 23 set in a magnetic field changes, so that the resistance value of the magnetoresistive element 23 changes. An earthquake is recognized by detecting this change of the resistance value as a voltage change, amplifying and shaping the waveform of this voltage change and detecting it as a pulse signal and processing this pulse signal by a microcomputer. |
