Light Sensitive Double LED Blinker

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Hii friend,

Today I am going to make a circuit of Light Sensitive Double LED Blinker.It means LEDs will blink alternate when no light will fall down on the LDR and LEDs will glow continuously when light will be on the LDR.

Let's get started,

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Step 1: Take All Components As Shown Below

Components required -

(1.) Transistor - BC547 x2

(2.) LDR x2

(3.) LED - 3V x2 {Any color}

(4.) Capacitor - 16V 220uf x2

(5.) Resistor - 220 ohm x1

(6.) Connecting wire.

(7.) Battery - 9V

(8.) Battery clipper

Step 2: Transistor - BC547

Pin-1 of this transistor is collector,

Pin-2 is Base and

Pin-3 is Emmiter of this transistor.

Step 3: Connect LED to Transistor

Solder -ve leg of LED to Collector pin of transistor.

Step 4: Connect LDR to Base of Transistor

Next solder one leg of LDR to Base pin of the Transistor as solder in the picture.

Step 5: Connect +ve Leg of LED

Next Connect +ve leg of LED to remaining leg of LDR as you can see in the picture.

Step 6: Make Like This of Another Transistor

Next we have to connect one more LED and LDR to another remaining transistor as shown in the picture.

Step 7: Connect Emmiter Pins of Both Transistors

Next solder emmiter pins of both transistors as solder in the picture.

Step 8: Connect Capacitor

Solder +ve pin of Electrolytic capacitor to Collector pin of 2nd transistor and

Solder -ve pin of capacitor to base pin of 1st transistor as you can see in the picture.

Step 9: Connect Again 220uf Capacitor

Solder +ve pin of this capacitor to Collector pin of 1st transistor and

-ve pin of capacitor to Base pin of 2nd transistor as solder in the picture.

Step 10: Connect +ve Leg of Both LEDs

Step 11: Connect 220 Ohm Resistor

Solder 220 ohm resistor to +ve leg of LED as solder in the picture.

Step 12: Connect Battery Clipper Wire

Now we have to solder battery clipper wire to the circuit.

Solder +ve wire of battery clipper to 220 ohm resistor and

-ve wire to emmiter pin of transistors as you can see in the picture.

Step 13: Connect Battery

Now connect battery to battery clipper and observe that -

1] When light will be on the LDR then Both LEDs will blink continuously as you can see in the picture-1 and picture-2.

2.] When light will not be on the LDR then LEDs will be linking alternately as you can see in the picture-3 and picture-4.

Thank you

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