Build this DIY 0-30V 0-10A Lab Bench PSU CV CC Build Using ATX PSU

Here is the 0-30V 0-10A Bench Power Supply board that I built using a schematic and project from PCBWay. Learn how to build a low cost Lab Power Supply with current and voltage adjustable up to 30V 10A using ATX power supplies.
Referenced in this video - Bench PSU project
• How To Build A Variabl...
This video is kindly sponsored by PCBway. Please give PCBWay a try for all your PCB needs. / pcbway
www.pcbway.com
If you use this link when creating a new PCBWay account and you will receive a free $5 discount coupon: www.pcbway.com...
Part One Is Here • The Ultimate Guide To ...
PCBWay Projects on Learn Electronics Repair
Amazing $1 Short Finder
• Convert Your MULTIMETE... Part 1
• The $1 DIY SHORT CIRCU... Part 2
• The Amazing $1 Short F... Upgraded Version
DIY Huntron Tracker / Octopus Curve Tracer
• How To Build the Amazi...
MilliOhm Meter
• Help!! My DIY Electron... Part 1
• Build A Cheap And Supr... Part 2
• Build A Low Cost Micro... Part 3
10KHz -255MHz RF Signal Generator
• Help!!! My Electronics... Part 1
• Build A Low Cost 10KHz... Part 2
300W Active Load
• Build A Low Cost DIY 3...
Amazing $1 ESR Meter
• Build This AMAZING $1 ...
Ring / Flyback Tester
• All You Need To Know A...
Amazing $1 Ring / Flyback Tester
• How To Find SHORTED TU...
Signal Tracer
• Build A Cheap DIY Sign...
Signal Injector In A Pen
• Build A Cheap DIY Sign... Part 1
• An Absolute Beginners ... Part 2
• An Absolute Beginners ... Part 3
Modified ATX PSU Analyzer
• This ATX PSU Tester An...
Single/Dual Op Amp Tester
• How To TEST OP AMPS Us...
Zener Diode & LED TEster
• How To Test Zener Diod...
TL494 Tester
• How to test TL494 / KA...
TL31 Tester
• How to test TL431 / KI...
Learn Electronics Repair is now on Discord! Come and join the fun, it's free.
/ discord
It takes a lot of time and effort to make KZbin videos. If you enjoy my videos or they helped you with your own repairs please consider subscribing to my channel or click LIKE
If you would like to help support this channel you could consider sending a Paypal donation or subscribing to my Patreon page. All monies received will go towards buying more items to repair and make interesting videos, or to improve my video recording equipment and will enable me to spend more time making better videos. If you subscribe to my Patreon you'll get my Whatsapp number and I'll give personal repair support
You can send donations via this link
www.paypal.com...
You can subscribe via this link
/ learnelectronicsrepair
Thank you for your support.
Richard

[@gregwmanning]

Yes I did enjoy learning how to isolate ATX power supplies, Thanks

[@alanrichardson1672]

Hi Richard, you have put a terrific amount of effort into this video with no doubt lots more to come. Well done and thank you. 👍👍👍

[@NZHippie]

Another wonderful video Richard... This technique of coupling two power supplies only works when both units are isolated output types and as you correctly point out the 0V output of both units must also be floating...

[@lordjohnpp]

Well Rick just use plastic spacers and joins to isolate the ground - you don't need any Dremel and soldering at all. Or you can use a UV resin solder mask for isolation too.

[@LearnElectronicsRepair]

You did hear me say, in the video, that using plastic shims or spacers, and nylon bolts, was another method you could use?

[@marauderofdeath6401]

Awesome video again! Always learn a lot from your videos!

[@steve6375]

Why not modify one PSU to output 24V? Would the components not stand the higher voltage. caps 16V rated, etc.?

[@LearnElectronicsRepair]

Are you reading my mind? This is another thing I'm gonna explain soon

[@nicopicco]

Am I like the only one that noticed that you went to and from the fountain of youth half way through this video LOL

[@vincents.3996]

Another excellent video, thank you ! But when you switch off one of the power supplies connected in series, don't you apply a reverse voltage to the output capacitor of the power supply which is off ? This voltage is limited by the shottky diode forward voltage, but at high current like 10A I guess this voltage could exceed 0.5 V. -0.5 V seems to be the minimum voltage that you can safely apply to an aluminium electrolytic capacitor continuously. There is not a lot of margin here and the use of relays might be a better solution !

[@LearnElectronicsRepair]

No- there is a reverse biased diode effectively to stop any voltage going the *wrong way* into the other PSU. Look at my diagram again and you will see that

[@vincents.3996]

The current will flow into the psu which is disconnected. You didn’t draw the capacitors, try drawing them and calculate the voltage applied to them!

[@LearnElectronicsRepair]

@@vincents.3996 I will on the next part to prove this point, but they are not reverse biased (well only by as much as the voltage drop of the Schottky diode) because the output capacitors in the PSU that is switched off are effectively shorted out by the secondary winding that isn't running, so what you have across those capacitors is a short, apart from the diode. You can safely put a reverse voltage up to 1V (and some google results say 3V) on an aluminium electrolytic. The way to test this of course would be to actually measure the voltage across the output terminals of the PSU that is switched off

[@unintendedperson]

This is the way 🎉

[@andymouse]

Excellent tutorial ! it's important to cover grounding because it's easy to get in a pickle. With the lower input voltage is the low voltage side that runs the logic working correctly ?.....cheers.

[@LearnElectronicsRepair]

Should be because this is all analog (not logic) and the LM723 regulators are able to run at even lower voltages than that. I think it may be something to do with the resistor values in the LM723 circuit but no doubt we will find out in the next part. The LM741 is only involved with switching the relay

[@andymouse]

@@LearnElectronicsRepair Cool and 'Logic' was a poor choice of words on my behalf !

[@davet3804]

Try the bench psu at 12v next Great stuff

[@LearnElectronicsRepair]

Yeah that is my train of thought too 😉

[@theshemullet]

Thanks

[@LearnElectronicsRepair]

Thank you for your support, it is much appreciated

[@TheDurdane]

I was already wondering if this was possible for a long time. In my case, I wanted to make 60V from +30V and -30V, but was anxious about the difference between earth and 0V. Also was wondering about the current. But you answered those questions already in this video, if I am not wrong: Isolating the output of both circuit is a perfect solution, and it makes sense that the max. current is that of the lowest Amperage of both circuits. So thanks Richard. I learned a lot (again)!!

[@pwal8468]

Hi Richard. Another really interesting video... If you don't mind a dumb question from an old Canadian, can you use the -12 and the +12 on the atx to get the 24 volts?

[@LearnElectronicsRepair]

Yes but the -12V is very low current so the 24V will also be very low current. However I have an idea about that which I want to try soon.....

[@Scott.Newmaster]

How about 2 nylon and 2 low standoffs for remouning the board. Would save cutting traces......

[@LearnElectronicsRepair]

Did you hear suggest exactly that in the video as an option to cutting the traces? 🤫 Plastic shims and nylon bolts as I put it

[@Scott.Newmaster]

@@LearnElectronicsRepair Sorry teach, was probably on the can. Was also looking at the idea of mounting the regulator on the top the p/s the same way....

[@tonysheerness2427]

Very interesting.

[@PCBWay]

Thx so much for your help

[@woodrowbrimm2805]

Interesting but much to Complicated for a beginner like me.

[@rickstevens644]

great channel, great experience, good knowledgeable explanations of circuitry and pcb's. great link's and perfectly balanced word knowledge and live problem diagnosis, repair and reconditioning of a wide array of electronic products and devices. underlining the empowering knowledge of possessing the knowledge to save money by repairing expensive electronics for minimal cost and a steady hand with the iron. Nice work and great videos. I do enjoy watching your channel. I'm one of those people who watch all the time, but only subscribe after a good bit of insight into the capabilities you possess. Besides your channel there is maybe one other channel that is as in depth and informative as yours. keep up the great work. and keeping me on my toes with my soldering iron.

[@bulwinkle]

Looking at the circuit diagram the opamp appears to be supplied with +ve feedback, or am I missing something?

[@christiantreldal1585]

Hmmmm...... what happens to the current limit, if gnd and chassis gnd are shorted.

[@Dutch_off_grid_homesteading]

Heya, those small diy project with these pcb's are great to start with learning and unterstanding differant circuit so I really love this I learn so much from it thanks

[@1998eclipse1998]

It probably requires 14 or 15 volt minimum to run the 723 and 741 chips

[@LearnElectronicsRepair]

741 works with 5V to 15V (actually the absolute rating is 4.5V-18V supply) Looking at the LM723 datasheet it only shows the max rating for Vs which is 40V but the example circuits in the datasheet use Vin of 12V so I don't believe that is the problem

[@fabiogerkemartins7248]

Hello Richard. I have some old agp motherboards I'm not using. If you want them i can send to you Just let me know. Thanks.

[@chinnarao326]

Resp Sir! Very Nice Vedio Sir Thank U for Coperation Sir. Sir I am Telugu Language Sir. I am Looking the U each Every One Vedio Sir. So many Knowledge from Ur Vedios. Sir Canon MF244DW Printer Powersupply Board 0.2 Ohms 2 Resistors Burned Sir. New FET K4005 Replaced Sir but Burned Sir. 1 Ohm and 10 Ohms and 22 Ohms Resistors was Replaced Sir but Burned Sir. Where the Problem Sir. Please Advise Sir. Please Sir. -- ChinnaRao Paderu Visakhapatnam Dist Andhrapradesh

[@dinf8940]

blast from the past design, tho it should be done with vacuum tubes for true historic accuracy. now, perhaps instead of building this, one should ask themselves if they _really_ need supply with 500uV ripple on 10amps, and upon answering that question in only sensible way slap a chap buck/bust module (optionally with extra lowpass filter) on atx psu and call it a day

[@LearnElectronicsRepair]

ATX PSU have been powering desktop PC and sensitive GPU for decades without ripple causing a problem

[@steve6375]

@@LearnElectronicsRepair But how much do they rely on all the caps on the mainboard plus voltage regulators?

[@unintendedperson]

How about the optocoupler, if the atx psu used for amplifier?

[@unintendedperson]

And maybe. Oscilloscope will tell us what quality will we get if use atx psu.

[@mikesilverthorn2491]

Hi Is there any one can help . I just can't get the hang of switchmode I keep watching videos. I have a switchmode which the high side get to 350 v but it don’t give output. Can anyone help

[@theshemullet]

Could you use conformal coating instead at this point kzbin.info/www/bejne/jKiliaWBp9iIfLs

[@bretdunkleberger4945]

o/