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02/09/06 16:17
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#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?            01/01/70 00:00      
   sorry I missed that..            01/01/70 00:00      
   many versions have been implemented            01/01/70 00:00      
      Simplest            01/01/70 00:00      
         Alternatively...            01/01/70 00:00      
            Switch            01/01/70 00:00      
         thankyou            01/01/70 00:00      
            Emergency stop            01/01/70 00:00      
            Soft start            01/01/70 00:00      
   Combine            01/01/70 00:00      
      if it has to be done the right wa            01/01/70 00:00      
         SPS?            01/01/70 00:00      
            if a SPS is a switching power supply - y            01/01/70 00:00      
      resistor value ??            01/01/70 00:00      
         DIY            01/01/70 00:00      
            Hmm...            01/01/70 00:00      
               the crux            01/01/70 00:00      
   check current rating of capacitors ...            01/01/70 00:00      
      search            01/01/70 00:00      

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