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Chico Magalh„es
02/28/12 22:58
Read: 827 times
Florianůpolis
Brazil


 
#186270 - AC Powered LEDs + strobe
Hello.
I want to make a LED light powered from AC without supply...
Yes, I know it is dangerous...

Firstly, I thought in using a long series of LEDs to achieve around the 280V peak then a "small" resistor.
I found this circuit in the google:

I will use just one LED series.
I want to know what does the first pair of capacitor (in the input, before the bridge), can someone explain me please?
(Looks like I can use ONE non polarized capacitor in the input and ONE polarized capacitor after the bridge).
I will use 1w pure white LEDs, 350mA, around 3,8v each.

Secondly, I want to turn this in to a strobe, I want to control it with a microcontroller by DMX.
I would need some help in how to switch this securely.
I dont care if microcontroller blows or even the LEDs, but there could be another DMX devices and it is not nice to burn then all.
I thought to use something like an IRF840 (switches much more than 280v) after the retificator, so when LEDs are off the capacitor will be charged, when turned on it will discharge the capacitor to the LEDs...

Maybe I'm saying much wrong things here, please dont be to severe.

Thank you.


PS: This is for my own use, not comercial.

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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