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Burglar Alarm Using LDR and BC 548 Circuit diagram

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