| 摘要 |
PROBLEM TO BE SOLVED: To operate even when earthquake occurs, and a signal line is disconnected, and to surely announce the occurrence of a fire when the fire is detected in this case. SOLUTION: This fire sensor is provided with a power source circuit for fetching a power supply voltage to be impressed from a fire receiver to a signal line, a vibration detection circuit for detecting vibration amounts due to earthquake, and for outputting a vibration amount level corresponding to the detected vibration amounts, a fire detection circuit for detecting physical amounts related with a fire phenomenon, and for outputting a physical amount level corresponding to the detected physical amount and a control circuit for detecting earthquake based on the vibration amount level, and for detecting a fire based on the physical amount level. This fire sensor is provided with an internal power source and a power source switching circuit for switching and connecting either an internal power source or the power source circuit, and for selecting it as a fire sensor power source. The power source switching circuit is connected to the power source circuit in a normal state, and when earthquake is detected by the control circuit, the power source switching circuit is connected to the internal power source. COPYRIGHT: (C)2005,JPO&NCIPI
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