Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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 13th December 2008, 05:24 PM   #1
diyAudio Member
 
Join Date: Jun 2008
Default One more PSU2 question

PSU2 is a fine tool but I think I'm banging on the wrong end.

Most power transformers are rated for potential and current, ie 300-0-300 ct and 100ma. Yet the PSU2 transformer box wants voltage and impedance. I'm using ohms law to calculate impedance: 300v/.1amp = 3000ohms. I gather this is not the way however because the circuits I draw do not produce the rated current and potential at the transformer. More like 30ma @ 200v.

Please clue me in.

Thanks
  Reply With Quote
Old 13th December 2008, 05:56 PM   #2
Stixx is offline Stixx  Germany
I am
diyAudio Member
 
Stixx's Avatar
 
Join Date: Sep 2003
Location: Southern Germany
Though I can't explain in real scientific terms I can tell you are mixing things up.

Curent draw is dictated by your schematic and is set in PSUD2 with I1.

The transformer box wants the resistance of the secondary winding... I do wonder where you found impedance? You can either take the resistance out of the manufacturer data, or guess it, or have PSUD calculate it (example in the attached image).

That should lead to more realistic results (since PSUD2 is a great tool).


best
Attached Images
File Type: jpg psud.jpg (43.3 KB, 109 views)
  Reply With Quote
Old 13th December 2008, 07:23 PM   #3
diyAudio Member
 
Join Date: Jun 2008
Thanks for the help, I get it now.

I just opened up an old tube powered Simpson signal generator I had sitting on the bench and measured transformer and inductor resistance and modeled that circuit and it all jives with reality.

I wonder if this could be used as a tool for estimating current ratings on those old junk bin transformers and inductors?

As for new part builds, I just need to dig a little deeper to find the resistance from the manufacturers specs.
  Reply With Quote
Old 13th December 2008, 10:08 PM   #4
diyAudio Moderator Emeritus
 
ray_moth's Avatar
 
Join Date: Jan 2004
Location: Jakarta
Quote:
I wonder if this could be used as a tool for estimating current ratings on those old junk bin transformers and inductors?
No, afraid not. It's true that a winding with high resistance won't be able to supply high current, but that's about all it tells you. The size of the iron core also limits the available current.
  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
newbie with input tran. question and wiring question imo Solid State 0 18th January 2006 10:10 PM
PSU2 and power transformer question. RockysDad Tubes / Valves 1 5th February 2004 11:23 PM
PS question - tformer question actually breguetphile Chip Amps 2 30th May 2003 01:29 PM
old speaker question, bullet midrange question & link to speaker project wallijonn Multi-Way 10 5th November 2002 06:03 AM


New To Site? Need Help?

All times are GMT. The time now is 05:44 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