Somebody help me understand the principles behind this DC blocker? - Page 2 - diyAudio
 Somebody help me understand the principles behind this DC blocker?
 User Name Stay logged in? Password
 Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read Search

 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
diyAudio Member

Join Date: Jan 2004
Quote:
 Originally Posted by benb Yes, maybe - the AC voltage across the caps will be pretty small, as a SWAG maybe only 0.1V. Knowing the capacitance, one could calculate reactance at line frequency, and from that and the current pulled by the transformer calculate the voltage across the caps.
So that's what he's doing... the larger the capacitance, the lower the voltage drop?

But the caps will still see reversed voltage, right? I wonder how long they will last like that, even with low V.

 26th September 2011, 02:10 AM #12 expert in tautology diyAudio Member     Join Date: Apr 2002 Location: New York State USA use AC rated caps, avoid the problem? it will just be larger and cost more... _-_- PS i think that current rather than voltage will be the bigger issue for electolytics... __________________ _-_-bear http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- every once in a while I say something that makes sense... ]
diyAudio Member

Join Date: Apr 2010
Quote:
 Originally Posted by 454Casull So that's what he's doing... the larger the capacitance, the lower the voltage drop? But the caps will still see reversed voltage, right? I wonder how long they will last like that, even with low V.
Yes, they'll see reverse voltage. As he says or implies, electrolytics are apparently not "really" damaged as long as the reverse voltage stays below a volt or so. Worst case is they short out, and the transformer is connected directly to the line, which it would have been anyway without this circuit.

Apparently the biggest source of reverse voltage would be any DC offset on the line.

 26th September 2011, 03:24 AM #14 diyAudio Member   Join Date: Jan 2004 Location: Toronto, ON, Canada nm So is this worth doing for a linear supply?
 26th September 2011, 04:35 AM #15 diyAudio Member   Join Date: Apr 2010 That calls for an opinion, and that's above my pay grade.
 26th September 2011, 02:16 PM #16 expert in tautology diyAudio Member     Join Date: Apr 2002 Location: New York State USA If ur transformers are humming, give it a shot... _-_-bear otherwise, ya know what else works? an isolation transformer - it doesn't pass DC offset... fwiw. __________________ _-_-bear http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- every once in a while I say something that makes sense... ]

 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 OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Glen B Solid State 8 28th December 2014 05:16 PM Artie Solid State 5 23rd June 2009 09:13 PM duderduderini Tubes / Valves 10 2nd October 2007 11:57 PM jeapel Pass Labs 5 4th July 2007 04:46 PM

 New To Site? Need Help?

All times are GMT. The time now is 12:41 PM.