what is a photoelectric smoke detector
A photoelectric smoke detector (also known as an optical smoke detector) contains a light source (typically an incandescent light bulb or light-emitting diode), a lens, and a photoelectric receiver (typically a photodiode).hen these batteries run down, the smoke detector becomes inactive. Most smoke detectors will signal a low-battery condition. The alarm may chirp at intervals if the battery is low, though if there is more than one unit within earshot, it can be hard to locate.