How to Make a LED Flashlight Circuit: Step By Step Guide

Last Updated on May, 2024

I’m a flashlight enthusiast, and I’ve always been fascinated by the insides of a flashlight. Recently, I asked myself a question — will I be able to make a LED flashlight circuit by myself?

I ended up doing immense research and testing at least twenty times before finally landing on the most efficient method.

At the end of this article, you will know how to make a LED flashlight circuit efficiently, regardless of your level of expertise.

That’s how simple and straightforward this guide is.

Quick Summary

You need a protoboard, LEDs, a resistor, a switch, and a battery holder to make a LED flashlight circuit.

Solder the LEDs and resistor to the protoboard, making sure the anodes and cathodes are touching each other.

Attach wires to the soldered lights and switch, and then solder the wires.

Before You Begin…

Dealing with electronics is a bit risky. So, before you begin, keep in mind to prioritize safety at all times. Pay attention to the smallest detail in this read, as that will keep you perfectly safe.

Is that all?

No! You’ll get to make a flawless LED flashlight circuit of at least four LEDs.

Let’s begin.

Things Needed to Make the Circuit

some things to make a Circuit
  1. A protoboard 
  2. About 4 LEDs (you can buy spare ones as needed)
  3. 24-ohm resistor 
  4. A switch (with two prongs)
  5. 3 AA battery holder
  6. 3 AA batteries 
  7. Wires that you should cut into about six inch pieces
  8. A multi-purpose tool
  9. Safety goggles
  10. A roll of solder (preferably lead-free for maximum safety)
  11. A soldering iron

How to Make a LED Flashlight Circuit?

Step 1: Keep the Materials Close and Wear the Goggles

You want materials to be within the working area. So, make sure they are easily accessible.

Most importantly, wear your safety goggles before the first step.

Step 2: Assembly 

This is how we actually begin the circuit-making process.

First, you need to put the LEDs and the resistor on the protoboard. As you know, the long leg of the LED is the anode (+), and the short leg is the cathode (-). 

So, you need to remember on which side of the protoboard the cathode and anode are as you start to put the LED in the protoboard.

Because the sides should be the same for all the LEDs, you will insert.

Flashlight Circuit Assembly

After that, you should bend the cathodes and anode legs to opposing sides. When you do, ensure that all of them touch each other. If not, the LEDs will not light up. You can twist anodes and cathodes separately and make them into two separate legs.

Next, take the resistor and bend the legs so you can insert them into the holes of the protoboard.

After that, fix the resistor parallel to the LEDs, and it doesn’t matter which side you choose to insert it.

Now, flip the protoboard and bend one of the protruding resistor’s legs to touch only one set of LED legs; it doesn’t matter whether it is the set of anodes or cathode. After that, bend the other leg of the resistor away from the anode-cathode legs of the LEDs.

That’s it for the assembly stage. Up next is soldering.

Step 3: Soldering Stage

Turn the solder on and let it heat up to about 3-5 minutes. Remember to hold the solder extremely carefully, like how you’d hold a pen, and have the safety goggles to protect your eyes from little metal pieces.

Bring the solder wire close to the bent anode and cathode legs of the LEDs. Melt the wire using the soldering iron and let the metal-glue bind the legs to the protoboard. If you see smoke, don’t worry; that’s how it works. But do NOT breathe the smoke.

The purpose is to solder all the LEDs together.

Step 4: Post-Soldering Testing

Before moving forward, you need to check if the soldering worked right.

To do that, take out your battery pack, which should have red and black wires. The red is positive, and the black is the negative end.

Now, connect the black wire to the group of anode legs, longer legs. When you touch the red wire to the resistor, the LEDs should light up if the soldering is successful.

Remember, the lights will not light up if,

red and black wires
  • The soldering is not done properly
  • You interchanged the touching wires with the legs 

So, don’t panic if the lights don’t turn on; rectify the mistakes.

Step 6: Attaching Wires to Soldered Lights

After that, take the wires of approximately 6 inches and peel off the ends of it up to about 1cm on each end. You can simply use the multi-purpose tool to do this.

Next, take one wire and attach it to one free end of the resistor. You can twist it around or bend it, but ensure the wires are touching each other well.

The next wire should be attached to the LED legs that are NOT touching the resister’s remaining end. 

Take the solder wire and solder the wires so they are not loose and permanently attached. To make sure you did the soldering right, try to pull the wire, and you’ll feel whether or not the connection is rigid enough.

Step 7: Attaching The Switch

Switches that come for circuits like these come with non-directional prongs. Unlike LED lights, these switches do not have a positive or negative end.

All you need to do is take one of the wires attached to the circuit and attach it to one prong. When you do, ensure that it is not touching the other prong. Leave the other wire for a moment.

For the final step, you should remember the polarity of the remaining wire; is it positive or negative? If it’s positive, connect the wire to the black wire; if it’s negative, connect the battery pack to the red wire.


Now, there will be a remaining end from the battery pack. You can attach the remaining wire of the battery pack to the remaining end of the switch’s prong.

Before you move to the final soldering, flip the switch; the light should turn on.

Here’s why it would not turn on,

  • If you have interchanged the connection polarities (positive and negative) of the board and the wires
  • The wires are not correctly connected

Fix these issues, and the LEDs should be lighting up.

Step 8: Final Soldering 

Once you know the circuit is working, you MUST remove the batteries from the battery holder. Failing to do so is extremely dangerous.

After that, it’s just a matter of soldering all the wire connections. Before soldering wires, make sure they are correctly touching each other. Twisting them with each other should do the trick.

When you do, you also should ensure that the hot metallic part of the soldering iron doesn’t come in contact with the wire because that will melt the wires.

So, there you have it — a completed LED flashlight circuit.

Note: 10 Parts of a Flashlight

How Do Flashlights Work?

When you turn the switch on in a flashlight, it creates an instant steady flow of electricity. This happens due to the contact between two contact strips connected to the sprint at the battery’s bottom.

Needless to say, the spring is directly connected to the battery. Its purpose is to allow the electricity to flow from the battery’s positive terminal throughout the flashlight and back to the negative terminal.

This locomotion of electricity would make the flashlight’s lights turn on.

When you turn the switch off, the contact strips will be separated, and the light will turn off.

Fascinating, isn’t it?

To learn more about this topic, checkout this guide.

Final Thoughts

Making an LED flashlight is a piece of cake when you have the necessary materials and know how to do it step by step — that is EXACTLY what this article delivers to you.

Now that you know everything regarding the subject, I’m sure you’ll enjoy making your own LED flashlight circuit — remember to wear your safety goggles when you do it!


Yes, you can use as many LEDs as you want on a flashlight circuit, but it is recommended to use 3-4 LEDs for best results.

The circuit design in a typical flashlight is a simple series circuit.

Yes, it is safe to make an LED flashlight circuit on your own, provided you follow the step-by-step guide.

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Dillon Morrison
I have been involved in the flashlight community since 2007. My brother has a flashlight shop from where I have tested and reviewed more than 600+ different types of flashlights. You can find more about me here.

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