Electronics > Projects, Designs, and Technical Stuff

Simple DIY Linear PSU

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exe:
Do you really need a 30V supply? I mostly use voltages below 5V.  Occasionally I use 9V, 12V and rarely 15V to provide supply for devices.

I'd say a two-channel 15V psu is much more useful. If I ever need 30V I'll just connect outputs in series.

I suggest have two or four isolated low-voltage channels, rather than one beefy channel. This also helps with heat dissipation.
In terms of heat dissipation, a better approach could be to use a pre-regulator like this one: http://www.bramcam.nl/NA/NA-01-PSU/NA-PSU-SCH-21.png . I successfully build it, I set the drop out to ~3V, and it works really well. The downside is increased complexity.

Finally, make sure your transformer is rated properly. It is commonly suggested to buy a beefier transformer as VA != W.

panoss:
I need a 30V supply. Ok, most of the times I need 5V, but not rarely I need voltages up to 25V.
I 'll consider your suggestions, of course.

I changed the values of C4 and C3 to 1n and 100n respectively, and looks very stable now!

xavier60:

--- Quote from: panoss on March 06, 2020, 08:02:26 am ---Has anybody tried the simulation?
Unfortunately, it doesn't seem to work very well.
The output voltage is not stable, for example it fluctuates from 14V to 16.4V.
I have replaced the main transformer with a Voltage Source, see the attachment (don't forget to replace the .pdf with .pdsprj)

--- End quote ---
Not saying it's a bad design, the whole auxiliary supply hanging off the LM723's reference pin, sort of, scares me.
This design doesn't need a separate winding for its control supply and can be further simplified,
 https://www.eevblog.com/forum/beginners/lm324-power-supply-with-variable-voltage-and-current/725/

Zero999:

--- Quote from: panoss on March 06, 2020, 08:02:26 am ---Has anybody tried the simulation?
Unfortunately, it doesn't seem to work very well.
The output voltage is not stable, for example it fluctuates from 14V to 16.4V.
I have replaced the main transformer with a Voltage Source, see the attachment (don't forget to replace the .pdf with .pdsprj)

--- End quote ---
I think it should work. Unfortunately, few people here use Proteus and changing the file extension will just confuse people. Zipping it to a .zip file is a more acceptable way to upload file types which are not supported by the forum.

panoss:

--- Quote from: xavier60 on March 06, 2020, 09:10:15 am --- https://www.eevblog.com/forum/beginners/lm324-power-supply-with-variable-voltage-and-current/725/

--- End quote ---
Have you built it? Does it work ok?

Could you please send me the Eagle files (I have Eagle 7.7.0) and the LTSpice files?
I 'll send you a pm with my email.
EDIT: I tried but you have blocked PMs?

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