Jump to content
Electronics-Lab.com Community

0-30V Stabilized Power Supply


redwire
 Share

Recommended Posts

Guest thiagoas

The things are getting very hot with the BD139 here  :P

It goes up to 80ºC
Too little heatsink?

It was able to control current down to 500uA, this is very nice. Thank you all for this great project.

post-113798-14279144683294_thumb.jpg

Link to comment
Share on other sites

Guest liquibyte

The things are getting very hot with the BD139 here  :P

It goes up to 80ºC
Too little heatsink?

It was able to control current down to 500uA, this is very nice. Thank you all for this great project.


Yeah, your heatsink has way too little surface area here, these get hot.  Go back a few pages and see what I used for mine.  While these are probably overkill, even then they get pretty warm to the touch.
Link to comment
Share on other sites

Guest thiagoas

Something went wrong now  ???

U2 is always at 30 V in the out pin, the opamp is ok, voltage in the pin 3 is variating normally.


I'm lost  :P

Edit:
Found it! Those crappy transistors burned without even get much warm.

Fake parts? Never heard of this brand.

post-113798-14279144684302_thumb.jpg

Link to comment
Share on other sites


Look the difference.

The MJ21194 has very powerful specs on its ON Semi datasheet. But yours has a tiny little chip inside and is marked Mexico and with the same date as the cheap ones sold by a Chinese company shown in Google Images. Why are American transistors made in Mexico sold cheaply in China?? Because they are fakes?
The name Motorola Semi was changed to ON Semi in 1982 when all their transistors became marked "ON" instead of "M". Maybe counterfeiters don't know that.

Here is an expert who discusses fake transistors: http://sound.westhost.com/fake/counterfeit-p1.htm
Link to comment
Share on other sites

Guest peterk

@ Audioguru

I took the liberty to tidy up your list and schematic.
If this meets with your approval then perhaps Site Moderators can pin it to the first page if at all possible.


Parts List:
Named both "Rev 6 July/2014" ( I found it confusing when one was rev5 and other rev2 ). I think that date should be included in the name;  "latest" is ambiguous.
Fixed colour red on D10, D13
Kept LED as D12
Labelled zener D13 since it was an addition after the original project
Listed differences for TLE2141 and MC34071

Schematic:
Added labels to RV1, RV2, RV3
Labelled zener D13
Designate D7

I have copied the "Best Of" out of the first 147 pages and made it into a .pdf for troubleshooting one's own.

post-113919-14279144692038_thumb.png

post-113919-14279144692217_thumb.gif

Troubleshooting_30V_PSU.pdf

Link to comment
Share on other sites

Guest liquibyte

@ Audioguru

I took the liberty to tidy up your list and schematic.
If this meets with your approval then perhaps Site Moderators can pin it to the first page if at all possible.


Parts List:
Named both "Rev 6 July/2014" ( I found it confusing when one was rev5 and other rev2 ). I think that date should be included in the name;  "latest" is ambiguous.
Fixed colour red on D10, D13
Kept LED as D12
Labelled zener D13 since it was an addition after the original project
Listed differences for TLE2141 and MC34071

Schematic:
Added labels to RV1, RV2, RV3
Labelled zener D13
Designate D7

I have copied the "Best Of" out of the first 147 pages and made it into a .pdf for troubleshooting one's own.

The PDF is a nice addition.  I'll let others weigh in on the schematic and parts list first but I think that these would make a nice addition to the front page and may help people with many of the issues that have been seen while building and setting these up.  MIght be nice to have a TOC with links of the questions to the relevant parts of the PDF and the answers for easy navigation.
Link to comment
Share on other sites

Guest peterk

Thanks Liquibyte. 147 pages condensed into 10. Most of the questions ppl were asking were repeated throughout this topic so hopefully the answer may be found herein.

I'll see if a TOC is workable. After reading 147 pages, deciphering, copying, editing, keeping what's relevant, I'm bushed.

Link to comment
Share on other sites

Guest liquibyte

Thanks Liquibyte. 147 pages condensed into 10. Most of the questions ppl were asking were repeated throughout this topic so hopefully the answer may be found herein.

I'll see if a TOC is workable. After reading 147 pages, deciphering, copying, editing, keeping what's relevant, I'm bushed.

I'm looking into adding bookmarks and a TOC using an editor I have.  Never really used it so I'm having to do a little research.
Link to comment
Share on other sites

Guest peterk

OK audioguru, but since you attach the list and cct now and then you'll decide which one you'll go with then.

@ liquibyte, I have the TOC done, I'll post it tomorrow.

Link to comment
Share on other sites

Guest dubok963

Hello! ! ! I collected and I am this power unit
Image
Everything works, Restriction works BUT when I close probes under loading (KZ mode) the light-emitting diode lights up and at the exit there is no pure zero, and 0,5 0,7в. Tell, you have pure zero, or after all millivolts? I won't understand in what the reason, I assembled 2 blocks and on them at KZ there is no zero... http://www.youtube.com/watch? v=MvffSXU2... e=youtu.be


on the semisinmentnikakh I disconnected indication... I soldered directly on a payment lamp loading-2 consistently (I reduced loading wires to 1см, for this purpose to avoid wire resistance) I Wanted to deliver already to armor wire with a zero resistance...... I connected a multimeter in a mode of the voltmeter, minus a clip on the bottom leg of the shunt (a foot which on a minus goes), and a positive clip---directly on +выхода BP........ I close, the light-emitting diode lit up, and напруга 0,3....... 0,5 0,7.... and there has to be zero............... and with the second the block similarly, the pure zero isn't present............... details all new, KT827A,TL081, a konder after the rectifier 15000mkf 50v, SKF soldering gumboil, payments is washed by acetone......

Prompt in what a problem..... Maybe someone already faced it.... Thanks in advance

Link to comment
Share on other sites

Guest dubok963

Yes, I from Russia.....
At short circuit "+" and "-" under loading protection joins, the light-emitting diode lights up, and tension has to fall to 0 volts, and at me it falls to 0,3 volts..... there is no pure zero..... How to correct it and to achieve chistono zero in a mode of "short circuit"? ? ?
Video

Link to comment
Share on other sites

You are measuring the voltage drop across the resistance of the wires connected to your short circuit. Your voltage meter is connected to the output terminals of your project, not to the short circuit.
Try connecting a very thick wire with a short length directly between the output terminals of your project.

My very accurate ohm-meter measures its thick connecting wires to be 0.3 ohms when I press the probes together very hard. Then if there is 3A flowing, the wires will produce a voltage drop of 0.3 ohms x 3A= 0.9V.

Link to comment
Share on other sites

Guest vakeiros

Hi guys,

I'm from Portugal and just ordered all the parts for this project.

Tomorrow i'll receive the parts (hopefully) and start the project, i though start designing the PCB today but it's better to wait for the components and make it the right size holes.

I bought parts (not transformers) for build 5 of these and i'll build 1 first and see how it goes... i'll use a couple of 25V tranformers i have here sitting arroung because i'll need this mainly at 12v and if it's OK i'll build a double PSU with a 400VA 2*30v transformer and it will be my bench unit.

I'll start Aluminum anodizing and i'll need 4Amps regulated for some parts, i really hope this unit will fit my purposes :P

Well i'm really excited about this and i'll let you know as the project go long :P

best regards

Link to comment
Share on other sites

Hi Vakeiros,
You can reduce the value of R7 to 0.33 ohms for a maximum output current of 4A but when the output voltage is low or is shorted then the driver and output transistors will get very hot.
For a 5A circuit we recommend using 3 output transistors (each with a series emitter resistor), then they share the heat.

With a 25V transformer you probably will not have an output as high as 30VDC when the current is 4A.

Link to comment
Share on other sites

  • admin featured and pinned this topic

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
  • Create New...