| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas alarm capable of being operated all the time even without using a commercial power supply, being installed at any place, also being installed without spoiling the fine spectacle, also being operated all the time even with a battery as the power supply and also suppressing an increase in the cost. SOLUTION: This gas alarm issues an alarm when it detects leakage, poor combustion or the like of gas. In this, a battery 1 for backup which has a long life as a power supply and a battery 2 for a main power supply which is used all the time are provided, and a changeover switch 3 which usually feeds the power from the battery 2 and also performs switching so as to feed the power from the battery 1 when the voltage of the power fed from the battery 2 becomes equal to or less than a fixed level is provided. |
