Burglar Alarm security circuit for home by IC 555

Burglar Alarm security circuit

The Burglar Alarm security circuit shown here is used as a burglary alarm. LDR is kept in such a place that when the thief enters our house, a shadow falls on the LDR. A small beam of light is also needed to deliver an uninterrupted signal to the LDR. To obtain the best light source, we can use a laser diode that works for a few kilometers. For home use, the infrared LEDs will be good and it will be difficult for thieves to work with the same efficiency at night.

Burglar Alarm security circuit

This Burglar Alarm security circuit uses a popular timer IC, which is 555. IC 555 is connected as a comparator to the positive supply connected to terminal 6, the output is high to 1, on the other hand, trigger terminal 2 is less than 1/3 of the supply voltage. The output goes to 0 if it is more than 1/3. A small change in the voltage of pin 2 is sufficient to change the output state of pin 3 from 1 to 0 and from 0 to 1.

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