Build Your Own Regulated Power Supply





Introduction: Build Your Own Regulated Power Supply

A regulated power supply is a very important component if you build electronics projects. But buying a good regulated power supply can be expensive. So in this instructable I'm going to show you how to build your own regulated power supply, why buy it if you can build it.

This project is very simple to build and requires basic electronic skills, there are good tutorials on how to solder all over the internet.

You can also watch the video tutorial below..

Step 1: Tools and Components

The list of materials for this tutorial is very simple, all you need for this project is

  • 0V - 30V Voltage regulator
  • An old laptop charger (or any other power brick)
  • Alligator Clips (optional)
  • A Multimeter
  • Soldering Iron
  • Soldering Wire

Step 2: Lm2596 DC TO DC Buck Converter

For this project we will be using a Lm2596 Buck Converter, this is a cheap voltage regulator found on eBay. You could also use a Linear voltage regulator such as L7805 but that has poor efficiency as compared to that of the buck converter. The Lm2596 is capable of converting voltages of up to 30V an providing a maximum current of 3A.

But the down side of a buck converter is it has an inductor on board so if your project is based on some kind of radio or electromagnetic sensitive. Then I would recommend you to use a suitable linear voltage regulator.

Step 3: Input

First, we need to select a suitable power source I'm using a laptop power brick as this is capable of giving me 16.5V and has a power rating of 65W. You could use any other power brick, just make sure the brick is able to supply the voltages, what your project needs.

You need to cut out the ends, at which it pugs into the laptop or the output side of the power source, remove the insulation and solder the joints. After that is done, you need to solder the power supply terminals to the input terminals of the board. Make sure you solder the polarity right.

Step 4: Output

I had a two sided alligator clip that I soldered to the output terminal of the buck converter. You could use different colored wires like I did, so you do not get confused with the polarity of the terminals.

After soldering the terminals connect the ends of the alligator clips to a multimeter and set the multimeter to measure voltages.

Step 5: Testing

And now you have completed your project and now it is time to test out your power supply. Plug in the power brick to a wall outlet and you should now see a reading on the multimeter. Adjust the variable resistor on the board to change the output voltage.

The voltage range is limited to the voltage range of the power supply and the maximum voltage output the buck converter can provide is 30V.

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my question is, will the voltage be the same on whatever load it is energizing?

Excellent idea, but Schematics would be nice and better for the beginners and intermediate. . . Those modules we can buy it today to anywhere cheaper price and good quality... Continue with your work my friend!!!

: D

You say you use a 65w power supply, but the buck prevent from using power. What is the maximum power you can use with your buck regulator?

4 replies

A 65W supply used with a 85% efficient converter should be able to supply about 55W, while this lm2596 can theoretically provide 90W. However that lm2596 board doesn't look like it can handle anywhere near 90W. The exact limit will depend on your maximum voltage, heat sinking, etc. Proper testing is key!

Usually the laptop supply gives around 19V. LM2596 being a buck takes a minimum of 1V and can provide 3A so you could pull out of that regulator around 54W best case scenario. Also over 1.5A it heats up pretty bad. Any heatsink does the job. I use a piece of 4mm thick piece of aluminium left over a little bigger than the board stuck on with thermal adhesive. Just be careful not to short anything underneath the board.

Thank you for your answer. That was what I taught by seeing this instructable: this regulator, as it is, cannot draw 65W (which is huge), the numbers given in the Instructable are only theoretical and do not work in the real world. That is important not to mislead readers, readers might look at this numbers not knowing they are not actual working characteristics and can be mislead if they make their own circuit. So if I understand correctly, you used it with a 4mm heatsink at 19V 1.5A, so 38W max? I personally do not use such converter above 10W as a good practice, and rather use them for signal lines, not power lines.

You can draw 1.5A without heatsink. I used a basic heatsink for aplications that require more than 1.5A. Did not test at exactly 3A but I'm sure I drew more than 3A at times only for short periods. This is a switching supply and the power wasted through heat is much lower than that of the linear regulators. The laptop supply gives 19V but the converter takes 1V so you can pull 18V maximum from it and 3A (only if the laptop supply can provide 3A), that's why I said 54W. This converter is good for aplications that need small currents and relatively high voltages (rarely used it over 15V). Great for tinkering: 90% of my home made experiments and circuitry need under 1A.


This is too simple and cheap to not build

instead of cutting off the end of the laptop supply lead you could solder a socket/lead onto the buck converter and plug it into the laptop supply. That way the laptop supply is still usable for other things like, say, a laptop :)

I used it and i had good result from it and long range .its good element and useful .

I just love these little converters. Cheap and small enough to incorporate them on my PC boards. And because it is switch-mode, there is almost no heat as with standard 7805 regulaters.

7 replies

standard regulates. produce heat just becose it regulate voltage and current.max output of a LM7805 is 5W (5v x 1Amp).if you give 12v 1Amp as input.that is equal to 12W .but a standard LM7805 max output is around 7 watts is waste and it converted to heat.

but in buck converter power (W) is always same(if efficiency is 100%).if your input is 12V 1A and you will need 24v as output ,so the output is 24V 500mA.thare is no power power loss means no heating

most of the buck converter have 80 to 95% efficiency


Just a small clarification: buck converters can only generate a lower voltage, so the 12v input and 24v output example wouldn't work. You would need a boost converter for that. But most laptop power supplies provide more than 12v and most electronic circuits use 12v or less, so in practice buck should be fine.

No, switching power supplies like this buck converter are not 100% efficient. These small cheap ones are probably about 70% to 85% efficient depending on the input and output voltage chosen.

That means there is power loss, there is heating. The amount of power the LM2596, and the inductor can handle depends on the IC heatsinking (to the copper clad PCB in this case) and the gauge of the inductor coils.

I agree. As most of my circuits uses 12V DC for relays etc, getting 5V for a micro controller with a LCD display and it's backlight is a problem.
However, with op amps and low voltage signals, I agree with gm280 to stick with linear regulators.

You can also try a combination of a buck regulator and a linear regulator. If you have 12V and want 5V, you can use a buck regulator to get down to about 6V and an LDO linear to get down to 5V. This will give you about 83% efficiency.

It's all tradeoffs. A buck regulator gives you more efficiency at the cost of more noise, a linear regulator gives you less noise but less efficiency (=more heat). Combining the two costs more parts and board area.

Eric, as with most anything dealing with electronics, you have to give something up to get something you like. Yes, switch mode power supplies may not source much heat, but that are very noisy. So if you want very low noise power for certain electronic projects, typical audio circuits and amplifiers, shunt type regulators offer that capability quite well. So different power supplies for different situations it seems.

I have bought and burned* 4 of these so far
I use it to charge dead phone batteries ( to bring them up to 3,6/3,7v)
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Some extremely dead batteries sometime draw up to 1,5A could that be burning the buck convertor?

1 reply

You are lucky the batteries aren't bursting into flames. No Li-Ion battery should be charged from a nearly depleted state without current limiting. Put a low single-digit ohms resistor in series with the battery, at least until it's charged past 80%.