Burglar Alarm Using LDR and BC 548 Circuit diagram

Description

 Circuit showing a Burglar Alarm.Here we have used a ldr and a switching transistor for making this schema

.When the light coming towards the ldr during the period the ldr have low resistance so the buzzer will on.When the light going away the ldr during the period the ldr have high resistance so the transistor will off.Here you need a 12 volt power supply

Burglar Alarm Using LDR and BC 548 Circuit diagram

 

 Components Required

      Resistor

                   10 k(preset)

      Transistor


                   BC 548

       LDR


        Buzzer

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Build a Burglar Alarm With Timed Shutoff Wiring diagram Schematic

This is a very important schema for security. This is a simple Burglar Alarm With Timed Shutoff Circuit Diagram. When SI (sensor) is closed, power is applied to U2, a dual timer. After a time determined by C2, CI is energized after a predetermined time determined by the value of C5, pin 9 of U2 becomes low, switching off the transistor in the optoisolater, cutting anode current of SCR1 and DE-energizing Kl. The system is now reset. Notice that (i6x C2) is less than (R7xC$). The ON time is approximately given by:(R7xC5)-(R6xC2) = Ton

Burglar Alarm With Timed Shutoff Circuit Diagram

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