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CBSE Class 12-science Answered

For investigatory project, please give information about burglar alarm,materials required for it,construction and its working.
Asked by Benjamin | 22 Oct, 2016, 04:46: PM
answered-by-expert Expert Answer
Dear benjamin.walter@jsw.in

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.

The scope of this helpdesk is to answer subject related queries which are relevant to understanding concepts and solving problems. 
However, we can explain you the working of a burglar alarm.
 
A burglar alarm is a device that monitors the designated area or areas to detect the presence of any suspicious elements. The system takes the help of the sensor to detect such elements.
The alarm consists of a photoelectric cell connected in a closed electrical circuit and an infrared source of light.
The light from the infra red source is continuously incident on the photoelectric cell, maintaining a constant current in the circuit.
The device is kept concealed near the place to be protected. If a burglar intercepts the invisible infrared rays, the photoelectric current stops.
This automatically operates a relay, which sends an electric current in another circuit connected to a bell. The bell starts ringing and alarm is raised.
However, you can construct a burglar alarm using an IC 555 also.
 


Regards

Topperlearning Team.
Answered by Yashvanti Jain | 24 Oct, 2016, 03:18: PM

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