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0-30V 0-3A Latest Data

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I will explain to you in English,
Hello dear developers of the scheme, I ask you to solve the problem, why I collected the circuit did not work on the IC mc34071, on the input circuit 25.5v, on the C1 39.8v, on the Ic3 4-foot -1.5v, on the output circuit -5v, help please what is the problem, why does not it work? I have no experience with electronics, help please?R1 2.2k 2w ,R3 230R 0.5w ,R2 83R 1w ,R7 0.11R 15w ,Q4 2sc5200 1,Q1 bc139 ,Q2 s9014 ,Q3 s9015 ,R22 1.2k 1w ,D1 10v0.5w ,D8 5.1v1w!

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On 2017-02-27 at 12:46 AM, repairman2be said:

Hi all,

Finally after some months have gone by, my build of the Power Supply is done.

I have used liquibyte schematic Rev. 8 and had made the cirquit board according to the Gerber.zip file he posted here:

0-30V Stabilized Power Supply

Page 88 posted October 6, 2014


I left out D10 and R15 as per his description.

I have plenty of boards leftover if someone has a need for it. There was only one mistake liquibyte made which have outlined in one of the pictures uploaded here.

I was fortunate enough to get a big case with a Toroidal transformer from the scrapyard. Also many parts are recycled from various sources.

Regards, William










I also made this project after your example (however i had to etch the boards my self, little bit hard from these gerbers but any way:-))

It worked nice but after a little longer session with a 12v 25w lamp the current control started to oscilate and be unreliable when i was testing.

Any ideas about where to start. I am not an expert so thats why I am asking.

The only thig i have tried so far is ro replace the tle op amp but same result.


Attaching some pictures of my project as well.....


And yes i realise that a cooling fan is needed:-)



Regards Niklas


Ok so now solved:-)


Now it works like a charm again and the problem was that due to a tight layout i had a small pice of aluminium on the backside of the board between two thin lines. (it did not burn anything so lucky i guess).

Just have to find a good way for the cooling fan.




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I am another one who has set out to build this supply and discovered the endless possibilities of revisions and possible enhancements to this design. Thank you for this post. The original links on pg 1 need to be revised to point to the relevant posts as I currently end up on the community index page. The links to all the pdf and other files work fine.

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Hello. The first thing is to introduce myself and say thank you.
I started with the original version and researching I have come here and I have to say that I have seen beautiful versions derived from v1. 0.
I would like to keep the original project (the TL081, the toroidal transformer of 24v. . . etc), but I've already seen so many projects that I'm a mess. What I'm looking for is simplicity and I don't mind staying at 27 or 28.maximum volts. . . but toroids are not cheap here and I want to take advantage of the one I bought from 24 which one do you advise me for that 24AC transformer?

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The 24VAC transformer probably produces 25VAC with a light load on the project. Then its rectified and filtered output is +34V and -5.6V which power the opamps. At times the voltages are higher. Your transformer will be overloaded if its power rating is 105VA or less (24V at 4.4A)..

The old TL081 opamps have an absolute maximum allowed supply of a total of only 36V so they will not last long. Replace the opamps with TLE2141 opamps that have a maximum allowed supply of 44V.

Many of the resistors and the driver transistor in the original project are overloaded. Upgrade them. The main filter capacitor C1 value is much too low, upgrade it.

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