Intro: Variable Lab Bench Power Supply!
Have you ever been creating your new project and held back by you lack of control over your power source? Well this is the project for you! Today I'll be showing you how to make an amazing lab bench power supply for very cheap! I made this whole thing for about $25 AUD and it looks and works great!
Step 1: Parts!!!
I'm listing all items on aliexpress due to it being worldwide however it's only a guide, as long as the values are similar you should be fine!
1- Audio Speaker Banana Plug
2- Mini Digital Voltmeter Ammeter DC
3- Terminal Blocks
4- B200K Linear Potentiometer
5- B500K Linear Potentiometer
6- LTC3780 10A Automatic Step Up Down Regulator
7- 16mm Metal Annular Push Button Switch Ring LED 12V
8- Old desktop power supply! I picked mine up online second hand for just a few bucks! there are tons of old computers people are happy to just get rid of so this works great for us!
Step 2: Printing!!
This print is super easy and could easily be made using alternate methods if you dont have a 3d printer! the dimension of the box is 300x100x100mm.
All the files are found here:
if you do download my files please chuck me a like and follow I love to see people enjoying something I could help make for them! I really do appreciate the support to make these kinds of things!
Print with whatever setting suits your printer best I had 20% infill.
Please note the rear of the encloser may not fit your power supply so please edit to fit!
Feel free to contact me regarding the design!
Step 3: Assembly!
As I've been saying I've kept this design very simple but I think the final product looks fantastic and much better than the ones available online.
I found it easiest to screw my power supply to the back mount then glue both the back and bottom pieces together and add hot glue under the PSU to prop it up straight. Next attach the front and sides.
Optionally you could make all the wiring for the front panel first before attaching it however it makes it very awkward to glue, but really this comes down to personal choice. I've tried it both ways and had no issues either way!
Step 4: Wiring!
Now for the fun part... Kinda
I've tried to make the above schematic as simple as I could, basically +12V goes to the LTC3780 and depending on the fixed outputs you want, attach the correct colour wire to the bannana plug! (The gnd you use for each does not matter, one black wire to each negative plug)
if your 24 pin header doesn't have enough of the values you need feel free to use either the molex or CPU wires!
My switch is a 12V LED switch but LED this is optional. For the LED power I used 12V from the CPU Header. Then connect the green wire to "C" on the switch and gnd to "NO
Step 5: Final Touches!
It's the little things you do that always make your final product seem more professional.
1- I added hot glue to most of my soldering joints to ensure even when moved around I wont have wires touching or put under stress!
2- Potentiometer knobs are a nice touch
3- Secure all lose wires to make it feel more solid. I didn't remove any of the PSU's wires in case I ever felt the need to change or expand on this design. This meant you could hear them move around. This made it feel cheap and is also a bit of a hazard so I bundled them and glued them out of the way. I also secured any other lose wires in the circuit!
4- Labels, obviously you don't want to be confused down the track or others for that matter so I just incorporated some simple labeling to remove any and all confusion!
Step 6: Wrap Up!
I love this final product and that why I wanted to share it with all you makers out there like me! I'd seen many variations for varible supplies but this is by far the easiest and is so much cheaper than the ones you can buy!
I've been using mine for a while now and it's been absolutely flawless!
However there are a few things I might add in the near future to make it even better!
1- Rubber feet, because the plastic tends to slide along the desk unless you hold the back
2- A support in the middle of the case, honestly it holds up fine as is but might feel more premium with a middle support!
That's it you've made a Varible Power supply on the cheap! Thankyou so much for reading my instructable I hope you enjoyed!! Please feel free leave me any tips so I can further improve my skills as I'm only a novice!