Burns, Doane, Swecker & Mathis
Photoelectric smoke detector
 A detection signal processing circuit for photoelectric smoke detectors reliably stable with respect to external noise is provided. Light receiving section of the detector for receiving light emitted intermittently from light emitting section and scattered by smoke particles comprises a light receiving element, a condenser charged depending on intermittent scattered light intensity received by the element and of a value over a predetermined level, and an output circuit providing an output to a following operation means only when charge amount of the condenser has reached a predetermined value. Optimumly, the predetermined value of the condenser charge is achieved when at least two or more of the intermittent scattered light are received continuously. 
Matsushita Electric Works, Ltd.
G
G08B
inventional
Takeshi Tohru Kazushige Kuniharu
Nakano Hanahara Morisue Tatetsuki