MCM Variable Bench Power Supply





Introduction: MCM Variable Bench Power Supply

As you learn more about electronics you quickly realize how valuable a variable bench power supply is. For the uninitiated a bench power supply is essentially a box that sits on your bench and let you control the power you supply to your project. Some power supplys allow for very little control such as choosing between 3.3, 5 or 12 volts. Others are much more accurate and allow you to control amperage and a load of other things I am still learning about.

Most electronics enthusiasts / Makers / Hardware hackers build their own power supply at some point as a right of passage, so I figured I would have a go. I love the Mid-Century modern aesthetic, so I wanted to infuse that look into my power supply to make it a bit different than the norm.

I should also mention that I have built this power supply using commonly available modules to speed up my build. This means I purchased electronic components that where assembled by someone else and connected them together to fulfill my needs. This is a quick and dirty way to do things. Much more accomplished Makers out there actually build the modules themselves. Respect.

Step 1: Bill of Materials

Here is the list of parts I used for this project. If you are a budding Maker you probably have some of these lying around already. In case you don't I've included links where you can find them.


  • IEC Male Panel Socket with fuse link
  • Toggle Switch link
  • Laptop Power Supply 16V@4.5A link
  • LM2596 DC Step Down Power Supply link
  • Voltage Ampere Monitor LED Panel link
  • Brushless DC Fan link
  • LTC3780 Regulating Power Supply link
  • 2 x Female Banana Socket link
  • 200K Potentiometer link
  • 500K Potentiometer link
  • 2 x Top Hat Potentiometer Knob link

Step 2: ​Case Cannibalization

Instead of hitting the wood shop to create a case, I found an old alarm clock that looked great but had a very annoying ringer. So annoying in fact that I stopped using it a week after buying it. I gutted it and was contemplating replacing the Plexiglas front panel with a different wood species, but my father brought up a better option. My father is a tailor, so he suggested using some type of textile over the Plexiglas. We thought this would work and be a lot easier than woodworking.

Before covering the Plexiglas I mapped out where I wanted to put all of the components and slowly drilled holes or Dremeled the panel where components needed to fit.

Then my father and I dug around and found a piece of Ultrasuede that had a really great texture. I lightly sanded the Plexiglas, sprayed some adhesive onto it and stretched the Ultrasuede over it and folded it over.

Step 3: Wiring It Up

I routed two holes in the back panel of the alarm clock and placed the IEC socket and fan. The IEC socket was interesting as it included a fuse mount. Safety first.

Next I broke open the laptop power supply and glued it to the case. Then I wired the AC input to the toggle switch, and then onto the laptop power supply.

The laptop power supply outputs 16v which I wired to both the LTC3780 and the LM2596. The LM2596 converts the 16v to 12v, which I wired to the fan and the Voltmeter/Ampmeter display.

Then the LTC3780 was wired to the Voltmeter/Ampmeter display and the banana sockets.

Next, I desoldered the small potentiometers that control the voltage and current on the LTC3780. I wired the new ones to the board and then exposed the pots through the front of the panel. I then attached some 70's era knobs to the pots.

Step 4: Finishing Touches

I think it came out rather well. My father's idea of working in a textile really adds something unique to the project. I think I'll collaborate with dad more often. The only problem is, now my other equipment is jealous.



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    Found this on Hack A Day, so congrates. One small change I would make, the bannana plugs and scokets that you are using are very cheap (10 for $1) I have used thouse in my own projects and they are not very good, lose connections, lossing "springiness" over time. I would get a nicer pair and use them instead,

    how to u wire up the voltage ampere monitor ? i have one but couldnt figure how to wire it up. thanks

    Hi Sooncheng, I know what you mean. I found a schematic online that showed it incorrectly wired up. I just added a schematic that explains the way mine worked. Hope it helps.

    thanks for the drawing of the cables etc. This will become an interesting job to rebuild for myself.

    please provide circuit diagram.

    I just added one. I hope it helps.

    I just added one. I hope it helps.

    is it possible to ad a drawing of the wiring? It is not good to see on the added pictures.