| 摘要 |
PURPOSE:To surely operate an alarm in case when a real fire has been generated, even at the time of testing to raise an alarm, by detecting an output voltage of a switching circuit, and driving a sub-alarm by operating a sub-alarm driving means when two or more control contacts is closed. CONSTITUTION:At the time of a test, after a main bell B1 is sounded, when a sensor of other line has raised an alarm before a contact r1 is opened, a control contact rm2 provided in accordance with its line in a switching circuit 3 is closed, an output of the second voltage level discriminating circuit 5 is inverted to an 'H' level, a transistor TR2 is turned ON through a latching circuit 7, and a sub-bell B2 is sound. Subsequently, when this transistor TR2 becomes ON by an output of the latching circuit 7, since a transistor T2 is provided on an input side from a release contact r1, the release contact r1 is opened by a time-up signal of a timer circuit 6, and even if sounding of the main bell B1 is stopped, sounding of the sub-bell B2 is not stopped. In such a way, warning of a real fire at the time of a test can drive an alarm without fail.
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