Where to fuse wall wart supply?

Discussion in 'General Electronics Chat' started by spinnaker, Dec 17, 2010.

  1. spinnaker

    Thread Starter AAC Fanatic!

    Oct 29, 2009
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    I built a wall wart power supply using the LM317 regulator.

    Actually it is not really a traditional wall wart but a old laptop supply.


    Normally PSUs are fused at the mains. I really don't have access to the main so where should I fuse it? At the input to my supply or at it''s output?
     
  2. mik3

    Senior Member

    Feb 4, 2008
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    Post the circuit to get a good answer.
     
  3. spinnaker

    Thread Starter AAC Fanatic!

    Oct 29, 2009
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    Here you go.
     
  4. t06afre

    AAC Fanatic!

    May 11, 2009
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    The laptop power supply should be fused/have protection on both the main side and the low voltage output. And also be protected from say overheating. I would have placed fuses before all in pins on the voltage regulators. From the top of my head. I think the maximum current for your regulators are about 1.5 ampere. Remember that overheating may also be a problem regarding linear voltage regulators
     
  5. Wendy

    Moderator

    Mar 24, 2008
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    Agreed. But if you want additional protection put a fuse in right where the initial power comes in.
     
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