psu problem / ripple current / esr - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 29th April 2004, 01:56 PM   #1
diyAudio Member
 
Join Date: Feb 2004
Location: Istanbul/TURKEY
Default psu problem / ripple current / esr

Hi,

Actually I have asked for this problem before in Tube forum. However, I havent found a solution yet.

I have the circuit below. V1 and R3 represents the transformer (220V to 300V, 180VA) and its equivalent series resistance (Rp=11.4ohm, Rs=16.2ohm). C1 and R2 represents the electrolytic capacitor I am using. That is a new Kendeil 05 type. R2 is max ESR specified by manufacturer (170mOhm).

I have built the circuit and also simulating on Orcad. In real circuit I am measuring 395Vdc at (+) pin of C1 and ground when there is 297Vrms in secondary of transformer. 297*1.414=420V. The first question is why I am measuring 395V instead of 420V ? (DMM is a cheap one, not a true rms device)

The graphs below is from Orcad. It seems there is a ripple current of 11A at first. Kendeil 05 is rated at 1.8A. Is it harmful for it ?

Is ESR=170mOhm low compared to other capacitors (Nichicon NT etc.) ?

Can I easily measure ESR of a capacitor ?

Thanks so much in advance.

MB
Attached Images
File Type: gif psu_combined.gif (40.9 KB, 217 views)
  Reply With Quote
Old 29th April 2004, 02:41 PM   #2
diyAudio Member
 
Join Date: Nov 2003
Location: flyover country
Hi, Metebalci -

It could be your DMM, as you suggest, and/or the waveform may be somewhat flattened on top. A single half cycle of 11A shouldn't hurt the capacitor, as long as the average ripple current stays below its rated value after the initial charging surge.
  Reply With Quote
Old 29th April 2004, 06:09 PM   #3
diyAudio Member
 
slowhands's Avatar
 
Join Date: Feb 2004
Location: Silicon Valley
The 1.414 multiple assumes no load at all on the supply, it's just the peak voltage of the AC in. You two diode drops in your bridge, and have a bleeder resistor of 220K. It only draws a small current, about 2ma, but it reduces the average voltage a tad. There is also very very slight leakage current through the diodes and the capacitor.

Do you know the accuracy spec of your DVM? If not, compare its reading to some well known reference voltage. It may also be misleading you.
  Reply With Quote
Old 30th April 2004, 09:56 AM   #4
diyAudio Member
 
Join Date: Feb 2004
Location: Istanbul/TURKEY
>The 1.414 multiple assumes no load at all on the supply, it's just
> the peak voltage of the AC in. You two diode drops in your
> bridge, and have a bleeder resistor of 220K. It only draws a
> small current, about 2ma, but it reduces the average voltage a
> tad. There is also very very slight leakage current through the
> diodes and the capacitor.

Is it possible to drop 30V in diodes, bleeder resistor, leakage currents ? It seems too high to me.

DC Voltage Accuracy is %0.5, AC Voltage Accuracy is %0.8

Thanks.

MB
  Reply With Quote

Reply


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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Ripple current ? woody Solid State 2 12th January 2009 10:09 PM
ripple current calculation? AndrewT Power Supplies 5 30th January 2007 04:24 PM
Ripple current in capacitors. beppe61 Power Supplies 5 3rd September 2006 11:37 AM
whats ripple current of c johndiy Solid State 9 2nd September 2006 11:37 AM
ripple current calculation metebalci Parts 1 24th July 2004 09:10 PM


New To Site? Need Help?

All times are GMT. The time now is 02:09 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2