| 摘要 |
PHOTOELECTRIC SMOKE DETECTOR AND ALARM SYSTEM An improved photoelectric smoke detector and alarm system which may be incorporated in a single station, completely self-contained unitary structure, or which may be incorporated in a multi-station detector system that is capable of self-contained operation but which can also be interconnected with other detectors whereby when any one detector's alarm sounds, all of the other alarms automatically sound in the other interconnected structures, the improved smoke detector and alarm system including a piezoceramic electrically activatable alarm, an illuminating circuit including a gallium aluminum arsenide light emitting diode, and a smoke sensing circuit including a pair of identical photoelectric cells formed on the same substrate with the photoelectric cells mounted in proximity to the light emitting diode whereby light emanating from the light emitting diode impinges upon one of the dual photoelectric cells at all times and impinges upon the other of the dual photoelectric cells to change the conductivity of the other photoelectric cell when particulate matter is present in the ambient atmosphere. An oscillator is included in the circuit which is actuatable in response to a differential in the conductivity of the photocells for actuating the piezoceramic alarm. |
