| 摘要 |
PURPOSE:To detect an earthquake with high sensitivity and to stop power transmission by providing a weight fixed on the reverse surface of a stress sensing resistance, a detection part which detects variation in the resistance of the stress sensing resistance, and a switch part which turns off a circuit forcibly with the detection output of the detection part. CONSTITUTION:A silicon semiconductor substrate 1 is soldered (X part) in a flat case 3 and stress sensing resistances 6 and 7 are formed on the substrate 1 by diffusing impurities. If an earthquake more than certain magnitude occurs, it becomes vibrations of the weight 2 and the resistances 6 and 7 vary in resistance owing to the mechanical deformation of the substrate 1 to make a bridge unbalanced, so that its variation signal is inputted to a resistance variation detection part 11. Then, a switch part is driven with a signal from the detection part 11 to turn off the circuit forcibly, stopping, for example, power transmission.
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