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Erik Malund
02/29/12 09:21
Read: 484 times
Mt Airy, Nc
USA


 
#186279 - I was around then
Responding to: Per Westermark's previous message
This design wasn't too uncommon 20 years ago,
I was around then and, neither then nor now, have I heard of two opposoite polarity caps on DC!
the crummy "solution" on tha AC side I have seen before and, as now, detested. Two caps in series will share the charge, how is one not getting reverse charged, does it short on reverse voltage? I have never understood this, but, since I have seen it used, it must 'work'.

Old LEDs could handle huge current spikes without a problem,
and, as seen, the designs are being copied (even for white LEDs)

Old LEDs .... could run with extreme multiplexing as long as the average current wasn't too high.
and the designs are being copied for newer LEDs

there wasn't pesky laws about power factor correction of loads
which, anyhow, are usually ignored by amateurs. Chico never states "for me" or "for production"

I'm not sure if it's just some LED types that fails to short or if they normally go to open,
A LED that fail "on its own" will usually open, A LED thet fail because of overload will usually short. The techie I had then, probably replaced 1000s of LEDs and in 99% of the cases the above was true.

Erik

can anyone explain
"Two caps in series will share the charge, how is one not getting reverse charged, does it short on reverse voltage? I have never understood this, but, since I have seen it used, it must work."


List of 27 messages in thread
TopicAuthorDate
AC Powered LEDs + strobe      Chico Magalh„es      02/28/12 22:58      
   Isolated Switch      Jim Granville      02/28/12 23:39      
      Switching      Chico Magalh„es      03/15/12 00:41      
   Some basics      Oliver Sedlacek      02/29/12 00:54      
      Not a good design - and expensive        Per Westermark      02/29/12 03:00      
         Answers + need some explantion      Chico Magalh„es      02/29/12 23:55      
      Cap voltage      Chico Magalh„es      03/01/12 00:03      
         More than 280V      Oliver Sedlacek      03/02/12 04:30      
            Measurement      Chico Magalh„es      03/15/12 00:45      
               Measurement correct      Erik Malund      03/15/12 07:54      
   two caps polarity reversed on DC!! ?      Erik Malund      02/29/12 07:13      
      More common long time ago      Per Westermark      02/29/12 08:33      
         I was around then      Erik Malund      02/29/12 09:21      
            Some polarized capacitors survives AC but not reversed DC      Per Westermark      02/29/12 10:01      
               POOOOOOOOOF      Erik Malund      02/29/12 10:27      
                  Yes, very likely a failure      Per Westermark      02/29/12 11:10      
                     that need bold face      Erik Malund      02/29/12 11:44      
            Back to back connection...      Kai Klaas      03/02/12 17:05      
   And another thing...      Andy Neil      02/29/12 15:30      
      Pseudo-CC with resistor requires much % V over resistor      Per Westermark      02/29/12 16:52      
      chip      Chico Magalh„es      03/01/12 00:11      
         one of these      Erik Malund      03/01/12 08:00      
         Chips      Andy Neil      03/01/12 14:33      
   PC PSU      Chico Magalh„es      03/15/12 00:47      
      Definitely better with lower voltage design      Per Westermark      03/15/12 01:11      
         PSU      Chico Magalh„es      03/15/12 18:37      
            Some bricks can inform about rating      Per Westermark      03/16/12 02:21      

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