Instructables
Picture of Homemade LM317 Bench Power Supply
Pic_0513_003.jpg
Pic_0513_004.jpg
PSBench.GIF
This is my first real project in electronics! I started by looking at the schematic and scratching my head a lot then just went for it!

I put the bits and bobs on the board and soldered them into place, wasn't really sure how or where to put the bits. Then i started soldering the wires as in the schematic that's easier said than done! after a few hours things started to come together, i finished the board and tested and to my amazement the psu worked! i would like to show afew pics and the schematic i used.
devicemodder made it!3 months ago

I made mine in a velleman kit box, also it has a fixed 5v output provided by a 7805, along
with a variable voltage output from lm317. the battery seen is powering the voltmeter.
it is controlled by relay so it powers on with the power supply and
shuts off with the power supply. voltage range depends on wall adapter.
current range is 1.27V DC to 16VDC. i prefer clear case so i can see inside.

IMG_2103.JPGIMG_2104.JPGIMG_2105.JPGIMG_2106.JPGIMG_2107.JPGIMG_2108.JPGIMG_2109.JPG
joshuam5111 year ago
Sorry, just to be clear, can you just replace the Lm317 with and Lm350 with out changing anything else or would it change the range or voltages or anything? Thanks :)
Bio9612 years ago
Can I use a 24v transformer without changing scheme ?
GamerM Bio9612 years ago
Now i'd rather use Lm350.
Cause it gives max 3 Amps.
LM317 has max of 1.5 Amps.
And yes you can use 24V with no problems.
Just make sure you use a cooler.
pfred22 years ago
You look like you're off to a great start to me. Even if you're just building a circuit on perfboard I find it helps to model the circuit first in board design software. It makes the final build go a lot easier, and come out better for me too. Easier to play around on the computer, than with a soldering iron.

Your first supply came out a lot better than my first one did. When I made mine there weren't any personal computers though, so I guess I get a little slack there.
Actually for something like a drill ,you don't need a regulator. If you use a 12v transformer all you have to do is rectify it with a bridge & add a capacitor to smooth it a bit & it will be happy. Drills under load take a lot of current , probably in the 10-15 A range. A good place to get high current transformers cheap is to get an old UPS, used for computer backup power & remove the step-up transformer. Wire it so the output side is now the primary & you have a great low voltage source. Usually they are within a couple of volts of what the battery voltage of the UPS was. i.e. 12v battery = 11v to14v ac . Current is roughly wattage of UPS / battery voltage. 300W/12v = 25A I have a bunch of these beasts around home & work , great for brute force power..


























Wizzkid1984 (author)  Lectric Wizard2 years ago
Thank you for the info i should have thought of that myself! i have in the past cracked open a few dc adapters just to see what was in them and there just an ac transformer and a four 1N4001 diodes and a cap
Welcome to the world of electronics !!! PSs are the best place to start, you get a lot of the basics without being overwhelmed. Nice clean job for your first project. If you need info feel free to ask. A lot of us here have been into electronics for a long time & love to share what we've learned.(45 years myself ) Yes, started when I was 4 years old... NOT !! CHEERS!!!
Wizzkid1984 (author)  Lectric Wizard2 years ago
Thanks, i got another project that i thinking about its converting a drill battery pack so that you can use a ac mains transformer (In its own housing) ive picked the LM338 Vreg witch in rated a 5A. I mainly use my drill at my bench and dont really need the battery, but its nice to have the best of both worlds. I was thinking build a 12V supply into the spare battery pack and use a DC Jack to input the ac. Do you think 5A will be enough? i had it running of a 2.5A PSU but once load was put onto the drill it was not very good