$10 DIY Variable DC Bench Power Supply

thingiverse

I was able to build mine for $10.46 because I had lots of used parts laying around from various projects. However, the parts list below shows everything needed. All I needed was the display, dc-dc converter board, and the potentiometers. The switch controls the main 12v power from the power adapter, which powers the dc-dc converter board and fan when switched on. The dc-dc converter board uses small potentiometers, so I desoldered them and replaced them with large ones that could be mounted off the board. The left potentiometer is voltage control and right is amp control, as seen [here](http://kimgrity.com/images/IMG_1935_04.jpg). The display is wired like [this](https://i.ebayimg.com/images/g/DLwAAOSw0kNXg1KO/s-l500.jpg), except that I powered the display on the input side of the dc-dc converter board. And that's it! Enjoy! Here the parts: * [DC-DC Step Up Down Board | $3.17](https://www.ebay.com/itm/DC-DC-Step-Up-Down-Boost-buck-Voltage-Converter-Module-LM2577S-LM2596S-Power-N2/400985223988?hash=item5d5c94f334:g:HhsAAOSwgQ9VpIkZ) * [Digital Voltmeter Ammeter | $5.75](https://www.ebay.com/itm/Mini-DC-100V-10A-Digital-Voltmeter-Ammeter-Blue-Red-LED-Voltage-Amp-Meter-Gauge/322951112374) * [10k Potentiometer | $1.54](https://www.ebay.com/itm/5pcs-10K-OHM-3-Terminal-Linear-Taper-Rotary-Audio-B-Type-Potentiometer/172618234352) * [Used 12v Power Adapter | $5.22 or cheap at thrift store](https://www.ebay.com/itm/New-AC-110-240V-To-DC-12V-2A-Power-Supply-Adapter-Transformer-For-LED-Strip-US/152337854739) * [Used 3D printer Fan | $2](https://www.ebay.com/itm/30mm-5V-Cooling-Fan-for-Raspberry-Pi-and-RepRap-3D-Printer/142351923704) * [Used Alligator Test Leads | $4.54](https://www.ebay.com/itm/10-Pcs-Dual-Head-Samll-Alligator-Crocodile-Clip-Test-Lead-Jump-Wire-5-Color-20/152902047801) * [1/2" x 1" Switch | $5.95](https://www.ebay.com/itm/2x-Red-LED-Light-3-Pin-ON-OFF-1-2-x-1-Rectangular-Rocker-Switch-AC-15A-250V/172808954640)