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0-30 Vdc Stabilized Power Supply


Sallala
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BTW- Multiple pages of conversation does not mean there are a lot of mistakes in a project. It means the project is a popular one. Try reading some of the posts before jumping in with a comment like that.
Others have built the project in it's original form and only report that it does not give a full 3 amps of current.

MP

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Hi Ron,
I changed the parts so that the project will be able to have an output of 30V at 3A with good regulation. It will also be able to have an output of 0V at 3A (shorted output or a very low output voltage at full current) without anything getting too hot and failing. The opamps were replaced with ones that are rated for the positive and negative supply voltages in the circuit. Is there a part that I changed that you need to know why?

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Hi audioguru,

I just finished this PSU. It is working perfecly. I used your parts list. Thank you very much!

Can I have one more question? I am going to use digital meter PM129A-1 as a Volt indicator. Not sure if I should set it up to 199.9 Volts permanently, or to switch between 19.99 V and 199.9V automaticaly. If I have 199.9 Volts permanently, will it be accurate enough?

Thanks again for your efforts.
Vaclav

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Hi audioguru,

I just finished this PSU. It is working perfecly. I used your parts list. Thank you very much!

Good and you are welcome.

I am going to use digital meter PM129A-1 as a Volt indicator. Not sure if I should set it up to 199.9 Volts permanently, or to switch between 19.99 V and 199.9V automaticaly. If I have 199.9 Volts permanently, will it be accurate enough?

It would be a nuisance to switch it. Just leave it on 199.9V and its reading will be within 0.1V.
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Dear Moderator:

All what i learned buy this 60 page, is that the greek designer (if he really is the designer) exposed a common wanted project which than fall in the hands of Mr. AUDIOGURO, aparently now the owner of the project. I live in in poor country, we are 40 years in war with guerillas and as hobby i can only use scrap, what i can get hold of. So special parts are out of my reach, large condensator-banks i have to assamble by mF 4800's, whe i get most out of the cheapest....
Now, i have a scrap Transformer out of the old days, 2x12V + 6,3 V, 110VA. I would like to use it, making the 6.3V Winding the negativ feed of a 7905 regulatar, end eventually using a diode in the feed to boost to -5,6V.  As i have a 35 amp bolt-on square rectifier chaep at hand, a two stage switch would be helpful to reduce execessive power to be burned of buy the 2N3055´s.

I divided this project into 3 stages:
1.) rectification
2.) cheap overide stage
3.) output stage

may i send You my drawing? Audioguro is some numbers to large for me, and i don't wat to be subjet of laughter.

best regards,
manfred,
HANSASHIP





That is not going to happen.
Also, mixos reports that this project worked fine for him in it's original form. He just could not achieve the 3 Amp output. No other problems. Notice that he posted a new topic in a different thread for modifications to get more current. (He did not give up on this supply because it would not work)

audioguru should note that I also get emails and PMs from users. Many who ask why so much change to a project which works ok for them or why is there a post that says a project will not work that they have built and are using. That is the problem with too much theory and not enough work bench.

I recommend to anyone who wants to build this project that they can go ahead and build it in the original form. Then if they need to make changes for their purpose, make them from bench testing. Not from theory.

I do not anticipate that there will be modifications posted to the projects section since the owner of this site has built this circuit and has reported that it works well with the one exception. In my opinion, if you need a constant 3A output, build a different power supply. Besides, there are way too many power supply schematics on the web to spend so much time on this one.

MP
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hanaship,
Please feel free to send your drawing to me at [email protected] or post it to this site if you would like.

Please also feel free to post your ideas without fear of ridicule. I have built a pretty good reputation for removing posts which ridicule others... Audioguru is not the owner of the project...he is just the most vocal.

This is an interesting project with much controversy. However, mixos, the administrator of this site put this project together in it's original form and has reported to me that it worked well with only the problem that he could not get the full 3 Amps out of it. Even with this, he seems pleased with the power supply Project. In another forum on this site, he has posted a thread on improving the supply to 5 Amps.

I think your contribution will be very valuable to others who also have a shortage of parts and who need to use parts which are available. This is one of those areas where you might not always get the best specifications out of a project, but you will get a working instrument that is useful for your means.

MP

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Hi Manfred,
You can make this power supply any way you want. I improved it so it can meet its spec's and be reliable without burning up.
It is a good idea to use your surplus transformer and switch its secondary voltage to reduce heating in the output transistors.

We should go over the details of your project since 6.3V when rectified might not make enough voltage for the input of a 7905, and 12VAC instead of 24VAC won't allow the circuit to make half its max voltage since the voltage loss of the output isn't halfed.

If you discuss your project on this forum, then many other experts can contribute their ideas about it.

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Hi Neo,
You were smart to use opamps rated for a 44V supply. ;D
The original opamps are rated for a max 36V supply but operate at 41V in the original project.

Mixos, the owner of this site built the original project and him and others reported that it won't give 30V at 3A, has a lot of ripple in its output and many parts overheat. Mixos's project failed before he finished measuring it and he hasn't talked about it since.

We have been discussing improvements in this thread so that the project can meet its spec's reliably, like Mixos said in the other thread before I joined this forum:

post-1706-14279142701246_thumb.png

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Actually, to keep the rumors down, I will interject here:

Mixos has mentioned to me recently that he put the project on hold due to a time constraint.  He has been doing other things and has not been able to put attention to it. Please do not exaggerate, audioguru.
I am not aware that his power supply has failed. Just did not give him the full 3 amps. The other thread is about improving the supply to be capable of 5 amps.

Again, thanks Neo for your valuable input. Others have successfully built this supply with minimal or no changes as well.

I tip my hat to those who are actually building this supply on the bench and who are not just building it in their heads or simulator. (I will not mention names).

MP

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No rumor, no exaggeration. The supply had original low-rated parts that over-heated and broke, and Mixos never mentioned the supply again. It has happened to a few people who made the original circuit.


Some who have made the original circuit also had success. You seem to be blinded to this because of the work you have done to make it better.
You also don't seem to understand what I mean by rumor and exaggeration. I have spoken with mixos on this subject within the past week. It is as I have posted. Nothing more.

Let's bring this thread back to constructive discussion on the power supply project and drop the argument and rumors of who did what.

MP
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Hi all,

Unfortunately some projects in E-Labs collection are not quite up to standards! The power supply discussed here is one of them which no one could have missed to discover. I have received mail and messages about a few others too but the PSU project has been very popular and thus much discussed. Sometimes I try to figure out what’s wrong and sometimes I have to divert the person to another site with a better circuit to fill the needs. I hope this is not going to miss credit E-Lab. Earlier to day a post was made that is similar to many of the mails and messages I have received:  http://www.electronics-lab.com/forum/index.php?topic=5915.msg36593;topicseen#msg36593
Perhaps it’s time to decontaminate the project department; there is no reason to have many projects, much better to have a few good once!

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