| 摘要 |
PROBLEM TO BE SOLVED: To provide a house fire alarm which performs no warning of exhausted battery at nighttime, when replacement of the battery is desirable at an early stage, even though it is not urgent because the battery still has a some margin of power voltage, and performs warning of the exhausted battery, when residents start their activities in the morning. SOLUTION: The house fire alarm comprises a battery voltage measuring section 15 for measuring battery voltage at designated time intervals, and an exhausted battery warning control section 11 for outputting the warning of the exhausted battery, when a value measured by the battery voltage measuring section 15 recovers a threshold value or more, after the value measured by the battery voltage measuring section 15 is consecutively lower than the predetermined threshold at the designated number of times. COPYRIGHT: (C)2008,JPO&INPIT
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