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A burglar alarm description

2016-02-18 00:48  
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4 in 1 Burglar Alarm

VN:F [1.6.9_936]This article is a burglar alarm is introduced. In order to you to master the principle of more efficient, we suggest that you combine text see schematic diagram. In this  circuit , the alarm will be opening under four different conditions: 1. When light falls on LDR1 enter the premises (at). 2. When light falls on LDR2 blocked. 3. When the door switch is open or wire is broken. 4. When a handle is moved. LDR1 photosensitive resistors should be placed near the door or the dark treatment, etc. If an intruder flashed his torch, it will light upon LDR1, reduce the voltage, the voltage drop across it so also triggers the 1 IC1 (pin 6). T2 will be forward biased so transistor and relay RL1 incentives and alarm operation. LDR1 sensitivity can be adjusted by different preset VR1. LDR2 may be placed in the side of the corridor so that the light from the light source is always falls on it. When the intruder through the corridor, his shadow falls on LDR2. Results in the increase of the voltage drop and pin 8 LDR2 IC1 lower and output pin 9 is high IC1. Operation is set alarm transistor and relay T2 was opened. LDR2 sensitivity can be adjusted by different potentiometer VR2. Long but very thin wire may be connected to the points A, B or C and D in A window or door. The long line of some may even be used to lock or tie. If any cuts or breaks this line, the alarm will be open as a pin 8 and 6 will be low. In parts of the line between points A and B or C and D door switch can be connected. These switches should be fixed on the door in such a manner, when the door is shut down the switch is closed, open the switch when the door is still open. If the switch or line, not used to these points, points should be short circuit. With the help of a line, even the point of contact (P) the handle of a door or other suitable objects made of conductive materials. When a person touches the handle or other connection object, pin 6 IC1 walk "low". So the alarm relay is opened. For good touch actions, potentiometer VR3 should be adjusted. If the potentiometer VR3 further toward the ground, the alarm will open even without touching. In this case, the attack should be improved. But tapping point should not be too much touch action will disappear. When you change the potentiometer VR1, to adjust the sensitivity of the contact with the correct help VR3 potentiometer. If police have other than the rated voltage of 6 v (more than 6 v), or if it has attracted a high current (more than 150 ma), connect it by relay points in the diagram shown in dotted lines. This principle is important, you know?
 

 


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