The Series 65 Optical Smoke Detector uses light sensing technology to “see” smoke entering the chamber. The external detector moulding is identical to that of the ionisation detector, and has an indicator LED which is clear in quiescent state and produces a red light in alarm.
The Series 65 Optical Smoke Detector has a moulded selfextinguishing white polycarbonate case with wind resistant smoke inlets. Inside the case a printed circuit board has the optical system mounted on one side and the signal processing electronics on the other.
The sensing chamber is a moulding configured as a labyrinth which prevents penetration of ambient light. The labyrinth has a fine gauze insect-resistant cover.
The chamber houses an infrared light emitting diode (LED) and a photo-diode which has an integral visible-light filter as an extra precaution against ambient light