In this tutorial, we are going to learn about Circuit Diagram for Burglar Alarm.
Burglar Alarm – As per below circuit of Burglar Alarm, There is the tone generator can simply be modified into an efficient burglar alarm. For this purpose, just a thin wire must be connected between the base of one transistor and the negative potential of the battery. As soon as the connection is made, the tone stops. The thin wire is LED around a window frame or a door step. If an intruder now opens the window or the door, the thin wire is broken and the alarm sound starts immediately.The breaking of the wire can be simulated by removing it from the circuit. As soon as the connection is broken, the alarm sound is starting up.
How does the burglar circuit work?
In this circuit can see there is a tone generator can be blocked by pulling the base of one of the transistor to negative potential. In this way, the transistor cannot conduct any more and the sound stops.
Best Experiments of Burglar Circuit – In this circuit, Due to the symmetry of the circuit, both transistors can be used to break the alarm tone. A simple experiment proves this easily. As alarm loop a thin enamel coated wire is well suited. This wire can be found in old electric motors, electromagnets or transformers. After removing the enamel insulation at both ends of the wire it can be connected to the circuit and the burglar alarm set-up is ready for action.
Main Parts of Burglar Circuit-
For Power Supply – 9V battery
Q1 & Q2 there is 2 NPN transistors
1 LED for indication
Resistors and Capacitors