0-30 Vdc Stabilized Power Supply

[vjedlicka]

Thank you audioguru,

btw the heatsink size is 16 x 10 x 4 cm (6.5 x 4 x 1.6 inch)
probably not too much?

 

[audioguru2]

the heatsink size is 16 x 10 x 4 cm (6.5 x 4 x 1.6 inch)
probably not too much?

It is too small. It would need a very high speed fan to dissipate 120W.

 

[logitec]

hello all
i see there are alot of mistakes in this project (almost 60 pages)
can any one tell me what i need to know to build it, problems and what was discussed

Ron

 

[MP1]

Read the posts
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

 

[audioguru2]

Hi Ron,
I recommend this parts list for the project to work well and be reliable. A few months ago someone recommended adding trimpots in series with the controls for calibration.

View attachment 38516

 

[logitec]

hello MP
I did some reading in this post and i saw a few people that had problems with this project
hello audio
can you tell me what difference and corrections those parts are making
i mean why have you changed these parts

 

[audioguru2]

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?

 

[MP1]

It will also be able to have an output of 0V at 3A

...sorry to inform you, but you cannot have 0V at 3A. You must have voltage to have current...

MP

 

[audioguru2]

...sorry to inform you, but you cannot have 0V at 3A. You must have voltage to have current...

MP

How much voltage is across a short? 1uV? 10uV?

 

[MP1]

How much voltage is across a short? 1uV? 10uV?

......always more than zero as long as you have potential......

MP

 

[ante1]

I think 0 Volts is not the same as 0.0000 Volts, it all depends on how many decimals you like to introduce.  ;D

 

[vjedlicka]

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

 

[audioguru2]

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.

 

[circuity]

hi,
i am goin to make a report for this circuit and i need a simulation result attached..
but i cant find some of the components in my simulators..
please suggest the best simulator program..

p.s. i changed the TL081 with MC34071P

thanx

 

[MP1]

Why not just simulate the report...    ;D

MP

 

[circuity]

I really need a program 2 simulate this circuit...... :-\
can anyone help?

 

[hansaship]

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

 

[MP1]

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

 

[audioguru2]

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.

 

[neo_himura]

i just finished building this cicuit...
and im happy to inform that it works perfectly fine...
i followed the original design but i changed the TL081 with MC34071P..

thanx u all