| 摘要 |
Each alarm unit has a sensing circuit which supplies a signal in the presence of a particular problem such as smoke, heat, or equipment failure. The signal energizes an electronic switching device, to couple power to a horn which then produces an alerting tone. The output of the sensing circuit is also coupled by a resistor to electronic switching devices in the other alarm units in the system, so that the occurrence of a problem at one location activates the horn in each alarm unit.
|
