Bench Power Supply




Posted in TechnologyTools

Introduction: Bench Power Supply

About: I am a 21 year old DIY ist and Tinkerer with a deep interest in the field of robotics, electronic and cooking. I am skilled in wood and metal work as well. I work in my basement workshop and i am mostly scra...

In this instructable I will be showing you how to build a bench power supply using some simple off the shelf components and a custom 3D printed cases. The goal was to make a compact and sleek looking power supply which is powerful enough for most applications.

This is my first project video on my youtube channel so consider giving it a look and subscribing if you are interested in more videos of the kind. This one is pretty simple as my focus was the video making part of it but the videos to come will be more original and involved. So look forward to those.

Youtube Channel: Badar's Workshop

Facebook Page:

Step 1: Parts Required

You will need the following parts for this build

  1. Power Supply Module 30V 5A AliExpress
  2. Power Supply 36V 1.4A 50W AliExpress
  3. IEC Panel Jack AliExpress
  4. Banana Jack Posts AliExpress
  5. Power Switch AliExpress
  6. Voltage Regulator AliExpress
  7. 12V 40mm Fan AliExpress
  8. Connector Kit AliExpress
  9. 3D Printed Case

Step 2: Designing the Case

I designed the case in SolidWorks. Before getting started, I glued some nuts in the housing of the power supply so that I can secure it with the plastic housing. The idea was to make a shell to house everything but not to enclose it entirely so I designed it with an open base.

I made all the measurements using a caliper and designed the case using a simple geometric approach. No fancy curves or anything, just something that is easy to print and ergonomic. That is why I angled the interface at a 45 degree angle to make it easy to see and use.

I paid attention to air flow because under load, the power supply will get warm and I dont want to worry about melting the plastic housing. So I incorporated a fan at the top and a exhaust grill on the side. The bottom has some open area too. The idea is that air will enter from the top and take the heat from the power supply and the module as it exits from the side and bottom.

One more thing to take into consideration while designing is that how will it all go together. Its easy to overlook size of the components while designing because you cant visualize the components. So I had to take account of connectors so that I leave just enough room for easy assembly and disassembly.

Step 3: 3D Printing and Reprinting

I printed the case with an orientation that would give the best surface finish. It took me a couple of tries to get it to print right as the model would detach from the bed while printing. After some trial and error, I figured out the right combination. The trick was to heat the bed just a little bit to 30 C and apply the painters tape on a clean surface.

The first successful print revealed some issues with hole placement for the mounting screws and some size issues. That is usually the case with 3D printed case and I was expecting it to be like so. I made the corrections and reprinted it. Everything seemed to fit right so I went ahead with assembly.

I have attached the stl file and the Solid Works file so feel free to modify it however you like it.

Important Note: I have one extra 3D printed case which I will be giving away to one of you guys who wants to build the power supply. All you have to do is subscribe to my channel and send me a message. I will ship it to the first person who reaches out to me. (US Only)

Step 4: Assembly

The good thing about working with custom 3D printed cases is that if you put thought into the design part of it, assembly can be very simple and satisfying. Just follow the simple steps:

  1. Secure the banana posts on the front panel using the nuts and washers that come with it.
  2. Screw in the IEC Jack on the back using M4 screws.
  3. Pop in the power switch.
  4. Start the wiring by crimping spade connectors to the appropriate length wires.
  5. Solder the fan regulator to the output line of the power supply.
  6. Set the output to 12 V and then solder the fan to the output.
  7. Screw in the fan using M4 screws and glue in the regulator.
  8. Finish up the wiring and connect the power supply and power regulator.
  9. Screw in the power supply using M3 screws and finish up by sticking some rubber feet.

The wiring is pretty simple so I wont go through drawing up a schematic. The AC input of the power supply is connected to the IEC jack through the power switch. The output of the power supply is connected to the input of the power regulator and the fan regulator. The output of the power regulator is connected to the banana jack posts. And the output of the fan regulator is connected to the fan.

Step 5: Testing

The power module is very versatile as you can adjust both, the voltage and the current. It can be used to test circuits and charge batteries among other uses. I tested it running on max load for a few hours and didn't notice any thermal effects.

Step 6: Conclusion

I hope you found this simple project interesting. This project was mainly aimed at getting a start into the video making part of projects as I plan on building a youtube channel.

Let me know what you think in the comments and give me some feedback about my video. I will be making more videos soon.

If you are making a similar power supply and need a 3D printed case, subscribe to my channel and send me a message. I will send it to the first person who reaches out to me. (US Only)



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    In step 5's picture you are putting your fingers around the cables, since you have to rotate the encoder with your right hand and there are the cables in between. Maybe having them under the display (in the non-45-tilted area) would have been a better choice, wouldn't it?

    4 Questions


    Hi again bad ars tinkerer , say does your 5 amp model ask for a blocking diode on positive out to prevent back flow from capactive or battery charging ? Mine doe's I just mentally compensate the small difference . Almost perfect device.

    Can you use two of these PSU modules and two independent switch mode AC to DC adapters (240v to 30V) to create a dual polarity power supply? (i.e. connecting the negative terminal of PSU A to positive terminal of PSU B to create a common ground)

    I think that would be possible. But to be honest I have not yet encountered a need for pos/neg supply other than Cicuits lab. And this wont be the best way to implement such a power supply as you would have to set them up seperately. Not so convenient.

    Could this work with a PC power supply?

    Well yes an no. My original plan was to use a mini ATX power supply but the module is a step down module. So the voltage range will be capped at 12 volts. Which doesn't really make it very useful. For an ATX power supply, I would recommend using a step-up/down module with a voltage/current meter. I will be doing a build on that soon.

    I don’t have a 3D printer can I purchase a printed case from you ? Thanks Gary Demarco Ohio

    I have an extra case that I can send to you. Its not the best quality when it comes to 3D printing but it will get the job done. Just message me your mailing address and follow my work on youtube and facebook.


    This is cool, added to my "I'll make that one day" list :D

    So you made a box and put things in it. The power supply seems to be irrelevant. Nice video though.

    3 replies

    Well its a bit more complicated than that. Measuring everything, designing it in CAD, 3D printing it, making corrections, reprinting, assembly. All while documenting it. Can seem pretty simple from a distance.

    I admire your video production, your design skills and application, but it is still just a build a box project. I am more interested in what goes in the box and found this a little sparce and digressing considerably from the main title which initially got my interest.

    Perhaps you'd find what you need over at Hack-a-day. I found it pretty well done and glad it got featured.


    Seems rather odd to use a mains power supply with a third of the power rating of the dc module. Normally one would use double to maximise the output power and efficiency and ensure adequacy. But it is small.

    3 replies

    For most purposes, 50 watts is more than enough. Smaller form factor was my priority. And a cleaner looking build.


    50 watt supply will starve the DC converter if it goes over around 40 to 45 watts. Which will make it unstable.

    Well thats true to some extent. I tested it with a drill motor. It was able to draw almost 50 watts but the voltage went down. So you are right about that. I even had a 24v 10 amp PSU but wanted the smaller form factor. So went with this design.

    Kid that is a work of art . I built something similar for my lab last month . With three rails, using a 5- 48 volt 10 amp adjustable PS as rail #1. Drok 15 amp micro controller with monitor just like the grey 5 amp you are useing as rail #2. And a Drok 5 amp version exactly like yours as rail #3. As long as My Rail #1 is the highest voltage and overall amperage doesn't exceed my 10 amp PS I can use all 3 rails at the same time. I love the control those little units give you over amps, volts and the shut down presets if any parameters exceed the values. These way beat old school power supply's that cost way more money . Overall I give you 15 out of 10 stars and will gladly give you top votes in the contest.

    2 replies

    Thank you for the kind words. Yes that is why i built my own instead of buying one from amazon. Although they were much cheaper, mine is more compact and offers greater control.

    Can't find where to vote for these left message on your FB convo

    pretty cool little power supply. i like it!

    1 reply facino tu trabajo gracias por compartirlo

    ya empese a fabricarlo cuando lo tenga listo te enviare unas fotos


    1 reply

    Gracias. Estoy deseando ver su versión de la misma. Hazme saber si tienes alguna pregunta.

    That's cute dude ;-) I have seen that the EEVBlog (YouTube) did a review on these units in 2017. If you want to watch it, the video can be found there: ?v=Cw2AjcczHg4

    1 reply

    Yes I saw that. But he reviewed the unit rated for higher power which has a separate board. This one is contained in a smaller package and has enough power for most uses.

    Very nice and clean design, great job.

    Why don't you move the banana plugs to the other side of the control panel?

    This way it will not interfere with the knob