How to Make a LED Flasher Circuit With Relay and LDR

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In this project, we are going to show you making a simple led flasher circuit using relay and LDR. It is very simple and cheap led flasher circuit, that you can make at home easily. You can control this LED flasher circuit using LDR.

Supplies

Thanks To JLCPCB.

$2 for 1-4 Layer PCBs.

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Component List

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To make this LED flasher circuit, we might need some electronics component. Those component list have to been, given below.

Component List:

1. PCB Board

2. LED – 5mm

3. Relay – 12v

4. Diode – 1N 5399

5. Resistor – 10 KΩ

220 Ω

6. Transistor – BC 547

7. LDR

8. RGB LED

9. Power Source – DC 12v

Transistor Pinout

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Transistor Pinout –

BC547 is an NPN transistor. As usual other transistor, this transistor also have 3 legs. This 3 legs have, different names. If we count from left side, then 1st number “Collector” 2nd number “Base” and 3rd number “Emitter”

Circuit Connection - Step 1

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To make this led flasher circuit, 1st we make a parallel connection with all 5mm led lights. Then we connect, diode with the “Coil” leg of relay. Then we connect transistor with the circuit.

We connect transistor “Collector leg with positive leg of diode. Now we connect resistor with the circuit. We connect resistor with “Base” leg of transistor and negative leg of diode.

Circuit Connection - Step 2

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Then, we connect LDR with the circuit. We connect LDR with “Base” and “Emitter” leg of the BC547 transistor. After this connection, we connect 220 Ω resistor with negative leg of the circuit.

Now we connect led light, with the circuit. We connect led light negative leg with positive leg of Diode and connect leg light positive leg with the empty terminal of 220 Ω resistor of the circuit.

Circuit Connection - Step 3

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It is the time to connect DC-12v power supply with the circuit. We connect DC-12v positive cable with led positive leg and connect DC-12v negative cable with “Emitter” leg of the transistor.

Our circuit is now completely ready for use. We connect RGB led light with 3v power supply and put the RGB led light on LDR.

Just see and enjoy the awesome flashlight circuit.