| 摘要 |
A battery operated smoke detector or the like is provided with means for monitoring the voltage of the battery and providing a warning when the voltage drops below a predetermined level. The detection and warning system includes means for sensing when the battery voltage has dropped below the predetermined level and producing periodic output signals in response thereto. A first alarm means produces a permanent warning signal in response to the first output signal, and a second alarm means produces periodic warning signals in response to the periodic output signals. |
