Showing posts from August, 2017

Working Principle of Smoke Detector

Basic Working Principle of Ionized and Photoelectric Smoke Detectors for Fire Alarm SystemSmoke Detector is the main sensing device in Fire Alarm System. To understand the basic working principle of smoke detector, we should remember Ionization and Photoelectricstructure, smoke detectors are manufactured basically based on these two principle. According to these rules there are mainly two basic types of Smoke Detector, you will find in the market.
Ionization Smoke DetectorPhotoelectric Smoke DetectorHow Ionization Smoke Detector Work
In ionized smoke detector, basically two positive and negative charged plates are consisted in an ionization chamber wherein a radioactive material like americium 241 is placed, shown in figure-1.1.
Air molecules collide with radioactive particles and extricate their electrons. Since the molecules lose electrons, they become positively charged ions; the same as other molecules gain electrons, they become negatively charged ions. Equal numbers of positive an…


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