Circuitry to monitor and control source of radiant energy in smoke detector

摘要

A photo-electric smoke detector includes a source of radiant energy (16b) and a closed loop control circuit (16) which responds to a radiant energy feedback signal to adjust an output characteristic of the emitted radiant energy (16c) and which evaluates a quality characteristic of the emitted radiant energy. The feedback circuit (16) and the source can be intermittently activated. Emitted radiant energy is directed toward a lens (18). The feedback signal is proportional to radiant energy (18b) reflected or scattered off of the lens.