Photoelectric smoke detector circuitry

Details Photoelectric smoke detector circuitry Photoelectric smoke detector circuitry

1985-04-05

1987-03-31

Rowland, James L.

Communications: electrical

Condition responsive indicating system

Specific condition

250574, 356439, G08B 1710

Patent

active

046546448

ABSTRACT:
A photoelectric smoke detector operating on a scattered light principle. The photosensor is connected at the input of an operational amplifier, such amplifier functioning as a threshold detector, saturation pulse amplifier and fixed pulse width compensator. Another feature of the invention resides in the provision of a special RC network connected from the output of a first transistor of a flasher section or subcircuit, which provides pulse power to the light source, to the input of a second transistor in such flasher circuit. As a consequence of this arrangement, when the LED serving as the light source tends to age, with a corresponding increase in its impedance, an appropriate signal is fed back from the aforenoted output of the first transistor to the input of the second, thereby to increase the pulse width of the output signal through the LED such that it is no longer, thereby compensating for the fact that it is no longer as bright.

REFERENCES:
patent: 4186390 (1980-01-01), Enemark
patent: 4506161 (1985-03-01), Muggli et al.

Affiliated with

Also associated with

Rating

Photoelectric smoke detector circuitry does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Photoelectric smoke detector circuitry, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photoelectric smoke detector circuitry will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2215669