Security Alarm With LDR

Hii friend,

Today I am going to make a circuit of Security alarm with LDR.

Let's get started,

Components required -

(1.) Battery - 9V x1

(2.) Battery clipper x1

(3.) LDR x1

(4.) LED - 3V x1

(5.) Resistor - 330 ohm x1

(6.) Resistor - 22 ohm/220 ohm x1

(7.) Transistor - BC547 x1

Solder -ve wire of LED to collector of the transistor as shown in the picture.

Next solder 22 ohm resistor to LDR as solder in the picture.

Now solder LDR to LED as shown in the picture.

Now solder 330 ohm resistor to emmiter of the transistor as shown in picture.

Connect base of transistor and other wire of LDR to 330 ohm resistor as shown in the picture.

Now solder battery clipper wire to the circuit as shown in the picture.

Solder -ve wire of battery clipper to emmiter of transistor

and +ve wire of battery clipper to +ve of LED.

Now security alarm circuit is ready.

Connect battery then use -

when we give light to LDR then LED is start glowing as picture.

After glowing LED it can also glow in the dark (night).

it will glow contineous till we will not turn off buy putting any object between LDR and LED in dark.

LED will be turn off in dark when we will put any object between LDR and LED.

As in picture I am going to put an object between them.

Now as you can see in picture when I put an object (paper) between LDR and LED then LED gone turn off.

Picture shows - LED is not glowing due to absense of light in LDR.

Again when I supplied light to LDR then LED is start glowing.

This is the whole process that which this alarm circuit is working vice and versa...

Thank you