The XP95 Optical Smoke detector uses an internal pulsing infrared LED and a photo-diode at an obtuse angle. In clear air conditions the photo-diode in the XP95 detector receives no light from the LED and produces a corresponding analogue signal. The signal increases when smoke enters the chamber and light is scattered onto the photo-diode. The optical smoke detector has an indicator LED which emits red light when the detector is in alarm.

The XP95 Optical Smoke Detector works using the light scatter principle and is ideal for applications where slow-burning or smouldering fires are likely.