Reverse Polarity Circuit

Discussion in 'The Projects Forum' started by rubicon99, May 17, 2012.

  1. rubicon99

    Thread Starter Member

    Apr 19, 2012
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    Hey I'm looking for an IC or a circuit that will have no voltage drop. I am inputing a 12-24 volt DC into a circuit. A simple diode will do the trick but there is about a .7 volt drop. Not a big deal but I need that input power for another part of the circuit. Rather not use a bridge rectifier cause it wastes more power.
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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  3. gerty

    AAC Fanatic!

    Aug 30, 2007
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    Are you looking for reverse polarity protection?
     
  4. rubicon99

    Thread Starter Member

    Apr 19, 2012
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    Yes I am... even if its an ic with minimal voltage drop.
     
  5. gerty

    AAC Fanatic!

    Aug 30, 2007
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    If you cannot stand the voltage drop of a series diode, you can put a reverse biased diode across the power terminals. That would of course be a dead short when connected wrong and must be fused. Otherwise you can opt for mcgyvr's suggestion, which is better than a reversed diode in my opinion as there is less chance of burning something up.
     
  6. BSomer

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    Dec 28, 2011
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    In that case, what mcgyvr has pointed out is one of the best solutions. MOSFETs have a very low on resistance so there will be minimal voltage drop across them. They also can handle a lot of current, which is better than the typical diode used for protection. I recall there was a video posted on YouTube showing how to use a P-channel MOSFET as reverse polarity protection. I think the author of the video was afrotechmods or something like that.
     
  7. kubeek

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    Sep 20, 2005
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  8. BSomer

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    Dec 28, 2011
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    Yup. That is the video. :)
     
  9. BJT_user

    Member

    Oct 9, 2011
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    Diode... and a small relay.
     
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