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U Kaz
02/09/06 09:17
Read: 870 times
London
United Kingdom


 
#109617 - Discharging capacitors?
Hello Guys

Few weeks back I asked for help from forum to build a power supply

http://www.8052.com/forum/read.phtml?id=107689

I did get brilliant responce, as i mentioned in my that thread as well that I have never build a power supply before so instead of building a very high current (24VDC, 15Amp) supply, I started with one having lower rating to get some knowledge (24VDC, 5.5Amps). As I was given different solutions/suggestions in my last thread, I followed them to make a striaght forward supply, which I have, I just have one problem.

I have build a 24VDC power supply using 160VA transformer, 35Amps rectifier, and 2 x 10,000 uF capacitors. I know there are much much better ways of building a proper power supply but for learning I thought this should be OK, the only problem is that when I cut off power (220V) going into the transformer the o/p is still ON for 3-4 seconds. Means power in is off but I still get 24VDC at the output. which i guess is because capactitors are big so they hold the charge for this much time but I want the o/p to go dead asap mains is switched off,

Could someone please suggest how can I solve this problem?

I would really appreciate any assistance.

regards
Kaz

List of 19 messages in thread
TopicAuthorDate
Discharging capacitors?      U Kaz      02/09/06 09:17      
   sorry I missed that..      U Kaz      02/09/06 09:35      
   many versions have been implemented      Erik Malund      02/09/06 09:40      
      Simplest        Andy Neil      02/09/06 09:55      
         Alternatively...      Hal Albach      02/09/06 12:23      
            Switch      Andy Neil      02/09/06 12:32      
         thankyou      U Kaz      02/10/06 01:39      
            Emergency stop      Per Guldmann      02/13/06 10:21      
            Soft start      Kai Klaas      02/13/06 19:34      
   Combine        Kai Klaas      02/09/06 19:46      
      if it has to be done the right wa      Erik Malund      02/10/06 06:36      
         SPS?      Kai Klaas      02/10/06 07:25      
            if a SPS is a switching power supply - y      Erik Malund      02/10/06 08:13      
      resistor value ??      U Kaz      02/13/06 08:53      
         DIY      Steve M. Taylor      02/13/06 17:02      
            Hmm...      Kai Klaas      02/14/06 20:11      
               the crux      Erik Malund      02/15/06 06:19      
   check current rating of capacitors ...      Frieder Ferlemann      02/13/06 09:13      
      search      Saif Ullah Khalid      02/14/06 09:13      

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