Electrolytic polarity - diyAudio
Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

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 15th September 2004, 09:48 AM   #1
Prune is offline Prune  Canada
Account Disabled
 
Join Date: Mar 2003
Location: Vancouver
Default Electrolytic polarity

When making a non-polar by putting two polars in series, do you put the two negative or positive terminals together, or it doesn't matter?
  Reply With Quote
Old 15th September 2004, 10:00 AM   #2
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
It doesn't matter how you do, plus to plus or minus to minus
__________________
/Per-Anders (my first name) or P-A as my friends call me
  Reply With Quote
Old 15th September 2004, 10:02 AM   #3
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
I don't think it matters...

If you want to ensure they get equal always-positive signals, put diodes across them to prevent reverse voltage. Note that when the capacitors are uncharged, one diode switches on and apparent C is just one; on the next cycle, the caps are charged and will look like two caps in series, i.e. C = C/2.

Electrolytics aren't good for continuous AC use, hence motor start caps are smaller than motor run caps, which are film in oil.

Tim
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote
Old 15th September 2004, 10:26 AM   #4
diyAudio Member
 
Geek's Avatar
 
Join Date: Sep 2004
Nope, doesn't matter. They will eventually fail either way
  Reply With Quote
Old 15th September 2004, 10:56 AM   #5
Prune is offline Prune  Canada
Account Disabled
 
Join Date: Mar 2003
Location: Vancouver
Which way do I do it for mains DC blocking (with the antiparallel diodes across them)?

BTW, I only found 6A diodes locally, whereas I need 10A. When I parallel them, do I need to put resistances in front? Somewhere I read that should be done, to drop 0.3-0.5V, otherwise as the diodes aren't a perfect match, one will conduct most of the current. But that means 0.05Ohm diodes, and I can't find anything like that.
  Reply With Quote
Old 15th September 2004, 05:37 PM   #6
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
Yes, a bit of resistance will level out current sharing. The only thing it costs you is dissipation and voltage drop, whether that will be a problem is up to you.

With or without diodes, direction doesn't matter, as long as the (cap+diode)'s both point in opposite directions.

Wazza mains DC blocking about?

Tim
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote
Old 16th September 2004, 03:58 AM   #7
Prune is offline Prune  Canada
Account Disabled
 
Join Date: Mar 2003
Location: Vancouver
Sometimes my mains has about 0.2-0.4 VDC and makes transformers buzz more. I got the attached schematic from the forums here; I'm not using the filter part, and I assume I can put both caps on the same line rather than around the transformer?
Attached Images
File Type: gif mainsdcblocker.gif (15.2 KB, 111 views)
  Reply With Quote
Old 16th September 2004, 07:16 AM   #8
diyAudio Member
 
Geek's Avatar
 
Join Date: Sep 2004
The mains DC is from an asymmetrical waveform due to incorrect power distrobution, loads or interference on the lines. Because of that, the circuit is, IMO, useless.
  Reply With Quote
Old 16th September 2004, 08:19 AM   #9
Prune is offline Prune  Canada
Account Disabled
 
Join Date: Mar 2003
Location: Vancouver
Well, you can hear it working. Toroids especially simply don't buzz as much (even better when I use an EMI/RFI filter instead of a regular IEC power connector).

On the other hand, lately I've not seen as much DC occuring; maybe someone took out a light dimmer or something.
  Reply With Quote
Old 16th September 2004, 08:40 AM   #10
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
Quote:
Originally posted by Geek
The mains DC is from an asymmetrical waveform due to incorrect power distrobution, loads or interference on the lines. Because of that, the circuit is, IMO, useless.
Have you tested it? It works actually.
__________________
/Per-Anders (my first name) or P-A as my friends call me
  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
Ess AMT polarity? Help promitheus Planars & Exotics 1 13th July 2007 10:52 PM
Hi-Vi B3N polarity Gollum Multi-Way 5 5th July 2007 06:58 PM
GE 97F cap polarity ??? maynardg Tubes / Valves 0 3rd February 2007 10:20 PM
LED polarity guitargully Solid State 4 12th January 2004 05:14 AM


New To Site? Need Help?

All times are GMT. The time now is 03:14 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