Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Unstable power supply output or normal?
Unstable power supply output or normal?
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 19th January 2013, 12:36 AM   #11
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Quote:
Originally Posted by Fusion916 View Post
Yes there are no pulses with no load, and increase in amplitude with load.

Is there anyway to diminish or eliminate these charge pulses?
You simply have not provided enough information. How much capacitance is between the rectifier and the regulator? How much load current? Ripple voltage max and min values, before regulator? Schematic?
  Reply With Quote
Old 19th January 2013, 09:00 AM   #12
Elvee is offline Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
The pulses have a fundamental of 60Hz, which means it cannot the capacitor path causing troubles, it is either the path of one of the diodes in the bridge, or induction from the AC input wires.
Can you post a pic of your set-up?
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophoneİ ♫♪
  Reply With Quote
Old 19th January 2013, 01:19 PM   #13
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
I missed the 60 hz aspect. Sorry. Now we do need a photo of the setup.
  Reply With Quote
Old 19th January 2013, 01:49 PM   #14
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: The great city of Turnhout, BE
Quote:
Originally Posted by Fusion916 View Post
Yes there are no pulses with no load, and increase in amplitude with load.

Is there anyway to diminish or eliminate these charge pulses?
As said before, these come from charging current through the wiring.
Did you try to change the scope ground lead connection? You may be picking it up that way, fasely thinking it is on the supply.
Connect the scope directly across the last supply cap: tip to the cap voltage, gnd lead directly at the cap neg terminal. Close as possible. Don't include any nominal ground wiring in your measurement.
If it is clean, good job.
If not, let us know.

jan
__________________
Cable: a potential source of trouble interconnecting two other potential sources of trouble - Erik Margan
Linear Audio pubs and articles . The SilentSwitcher now at diyaudio store SilentSwitcher. Keeping in touch with SY.
  Reply With Quote
Old 19th January 2013, 01:51 PM   #15
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: The great city of Turnhout, BE
Quote:
Originally Posted by Elvee View Post
The pulses have a fundamental of 60Hz, which means it cannot the capacitor path causing troubles, it is either the path of one of the diodes in the bridge, or induction from the AC input wires.
Can you post a pic of your set-up?
The charging pulses charge the cap and then return through the ground wiring. That's what we're seeing here.

jan
__________________
Cable: a potential source of trouble interconnecting two other potential sources of trouble - Erik Margan
Linear Audio pubs and articles . The SilentSwitcher now at diyaudio store SilentSwitcher. Keeping in touch with SY.
  Reply With Quote
Old 19th January 2013, 03:30 PM   #16
Elvee is offline Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by jan.didden View Post
The charging pulses charge the cap and then return through the ground wiring. That's what we're seeing here.

jan
If it was the case, their frequency would be 120Hz, not 60.
The fact they are symetrical gives another clue: it cannot originate from one diode, because the waveform would be asymetrical.
This leaves one possibility: induction from the AC input.
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophoneİ ♫♪
  Reply With Quote
Old 19th January 2013, 03:44 PM   #17
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
So does it then have to be layout and wire dress, i.e enclosed loop areas making antennas? Or could it still be scope-probe-related, only?
  Reply With Quote
Old 19th January 2013, 04:41 PM   #18
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: The great city of Turnhout, BE
Quote:
Originally Posted by Elvee View Post
If it was the case, their frequency would be 120Hz, not 60.
The fact they are symetrical gives another clue: it cannot originate from one diode, because the waveform would be asymetrical.
This leaves one possibility: induction from the AC input.
Of course it isn't one diode! One up, one down, per chance?
Do you realise that this is going on in ALL power supplies, and that it is a matter of where you chose your grounding, also for measurement, that determines whether you 'see' it or not?

jan
__________________
Cable: a potential source of trouble interconnecting two other potential sources of trouble - Erik Margan
Linear Audio pubs and articles . The SilentSwitcher now at diyaudio store SilentSwitcher. Keeping in touch with SY.
  Reply With Quote
Old 19th January 2013, 07:15 PM   #19
Elvee is offline Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by jan.didden View Post
Of course it isn't one diode! One up, one down, per chance?
Do you realise that this is going on in ALL power supplies, and that it is a matter of where you chose your grounding, also for measurement, that determines whether you 'see' it or not?

jan
Do you realize that there is only one single loop in the supply circuit where this type of signal can be observed?
I let you guess which one
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophoneİ ♫♪
  Reply With Quote
Old 20th January 2013, 01:42 AM   #20
Fusion916 is offline Fusion916  United States
diyAudio Member
 
Join Date: Feb 2012
Hmm, ok forget the regulated power supply for a second, I am getting these waveforms at the output of the rectifier diodes with just loading the output rectifiers and caps alone.

I'm starting to think perhaps the diodes I am using are the suspect?

I have 15000ufx8 at the output of the rectifier diodes and I am using 4 of these Digi-Key Part Search for full wave rectification.

With just adding a load at the rectifier output to draw about 400mA I am getting the waveforms pictured at the OP.

So lets forget stability issues or whatever. Diode, cap, or layout issue?
  Reply With Quote

Reply


Unstable power supply output or normal?Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Dx Supply, output adjustable, stabilized power supply destroyer X Power Supplies 264 28th December 2015 12:29 PM
Lateral MOSFET power supply and RMS output power. tallerseverino Solid State 29 25th March 2012 04:32 PM
Multiple amps + single power supply = unstable output d0s4gw Solid State 2 22nd June 2005 07:07 AM
Using the secondary of a normal transformer as the primary to get a HT supply baggystevo82 Parts 9 2nd April 2004 11:02 PM
What's a normal output impedance for a CD player? Lisandro_P Everything Else 9 17th August 2003 10:40 PM


New To Site? Need Help?

All times are GMT. The time now is 06:58 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki