Which type of photoelectric smoke detector focuses a beam of light across the monitored area into a cell, and initiates an alarm when the beam is obscured?

Question

Quizplus · Accepted Answer

Projected-beam smoke detectors work by focusing a beam of light across the area to be monitored into a light sensor. When smoke particles obscure the beam of light, the reduction in light reaching the sensor triggers the alarm. This method is distinct from ionization or other types of smoke detectors, which operate on different principles.

Which Type of Photoelectric Smoke Detector Focuses a Beam of Light