Show your homemade power supply - Page 1
Forum section: electronics / projects

author: gcewing
author_rank: Regular Contributor
timestamp: September 25, 2021, 10:28:23 am
content: I had my Frankensupply open for an upgrade, and thought I'd take some pictures to post here. Stitched together from the dismembered corpses of various pieces of equipment, it provides power for many of my mad scientist experiments.The transformer and most of the rectifiers and capacitors are from a dot-matrix printer. The power cord, power switch and input filter are from a daisywheel typewriter. The case once housed an 8-track cartridge player. The regulators and heatsink were bought for the purpose (I needed a fresh, young heart).The upgrade was adding a 36V output for jolting stepper motors into life.Anyone else have a unique power solution they'd like to share?

author: ledtester
author_rank: Super Contributor
timestamp: September 25, 2021, 02:39:11 pm
content: How does this work? Are you using two Euro style terminal blocks to create a plug so that you don't have to unscrew any of the colored wires to disconnect the front panel?

author: gao415517
author_rank: Newbie
timestamp: September 25, 2021, 02:47:08 pm
content: Handmade

author: gcewing
author_rank: Regular Contributor
timestamp: September 26, 2021, 04:11:02 am
content: Quote from: ledtester on September 25, 2021, 02:39:11 pmIt's one of these:https://www.jaycar.co.nz/plug-socket-12-way-screw-terminal-strip/p/HM3202

author: Terry Bites
author_rank: Super Contributor
timestamp: September 26, 2021, 04:40:40 pm
content: Current limit is dodgy though....

author: SmokedComponent
author_rank: Regular Contributor
timestamp: September 27, 2021, 11:09:38 am
content: My weekend take at "μSupply" years ago; 0-10V, 0-0.5A linear supply with op amps. Normally runs on Ni-MH but now I'm pushing my luck...

author: AccountRemovedPerUsersRequest
author_rank: Regular Contributor
timestamp: September 28, 2021, 04:08:25 am
content: 3-13VDC

author: BU508A
author_rank: Super Contributor
timestamp: September 28, 2021, 08:16:06 am
content: Some more PSU (also homemade):https://www.eevblog.com/forum/chat/show-your-favorite-and-mostly-used-benchtop-psu/

author: Avelino Sampaio
author_rank: Frequent Contributor
timestamp: September 29, 2021, 08:45:40 am
content: HiIt took me 6 months to complete this project. It was an amazing learning experience! My challenge started with the implementation of a Mosfet, for Soft Start control. Mosfet had two other functions: RDS_on in the composition of the CRC filter and interrupt key for the OVP and OTP system.Details of the development at the link belowhttps://www.diyaudio.com/forums/power-supplies/368845-functions-mosfet-crc-filter-soft-start-sense-5.html

author: Thomas
author_rank: Regular Contributor
timestamp: October 02, 2021, 08:23:58 pm
content: Designed and built back in the college daysMade the PCB at school, in the PCB lab. Did not work first time, quite a few revisions to get rid of the oscillations0-25V, 0-2.5A with an ATmega8 for setting the references for the output (PWM), and for measuring voltage and current (internal ADC).It also has a RS-232 port and a DS18S20 temperature sensor for controlling the fans.Still works fine, and I use it quite a lot.

author: TheMG
author_rank: Frequent Contributor
timestamp: October 03, 2021, 07:09:00 pm
content: My first foray into building a bench power supply (about 10 years ago). Essentially two completely independent linear regulated power supplies in a single enclosure, each capable of 30V up to 3A.The case, transformers, heatsink, pass transistors, bridge rectifiers, and a few other components are salvaged from e-waste.In the first picture, modifying the toroidal transformers. I added a couple of taps to the main secondary winding, these are selected by relays to reduce power dissipation in the pass transistor at lower voltage settings or when the power supply is in current limit. I also wound an additional auxiliary winding on top to provide power for the control circuits.Pic 2: front panel assembly.Pic 3: once the front panel and transformers were assembled as well as the pass transistors on heatsink, it was time to prototype and test the circuit on breadboardPic 4: etching PCBs using the toner transfer method, and extremely caustic hydrochloric acid / hydrogen peroxide mixture as etchant (rather dangerous compared to ferric chloride, but all the necessary chemicals can be obtained at any hardware store, and the only option for me obtaining ferric chloride is to order it online)Pic 5: assembled PCB. the connectors are of course yet another salvaged part, and they are a much nicer alternative to soldering the wires direct to PCB, in case further modifications or repairs of PCB are ever necessary, it can be easily removedPic 6: PCBs mounted above transformers on custom made aluminum brackets, time to finalize the wiring!Pic 7: with the wiring all cleaned up and rear panel installedPic 8: done (except for labelling the controls). big knobs are voltage settings (10-turn pots), small knobs are current limit setting (single turn)It's not going to win any awards as far as how clean the output is (does have a few mV 120Hz ripple, probably due to using the output of LM7812 as the voltage reference rather than an actual proper voltage reference), but it's good enough for my needs and I still use it fairly regularly even to this day. I could make some improvements to it but just haven't bothered.