Optical Smoke Detector
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.