Welcome to Electronics and Electrical Engineering Laboratory.
|Power / Voltage - Voltage Converter|
This security system is very important for any kinds of home , office , factor. there has a circuit diagram its simple and easy to build . Any one can do it. It's a low cost circuit diagram.
Many security systems use a closed loop of wires and switches arranged so that whenever a door or window is opened, the loop will be broken and the alarm will sound. An obvious problem is that someone can tamper with the system, short out the loop, and later on, come back and burglarize the premises without sounding the alarm. Hiding a known resistance in the loop, as you propose, is a very good idea. That way, the alarm can distinguish a short circuit from a correctly functioning closed loop.
This is 1.5 Watt FM Transmitter circuit diagram. This diagram should be able to cover 1-2 KM range. This circuit diagram is very easy and it works very nice.