What are those cylindrical devices seen on power mains?

Discussion in 'General Electronics Chat' started by lewiso, May 24, 2013.

  1. lewiso

    Thread Starter New Member

    May 24, 2013
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    I gather that they're used to suppress transient spikes? Are they effective on AC? Would they work on a DC circuit?
     
  2. LDC3

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    Apr 27, 2013
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    Could you post a picture?
     
  3. Dodgydave

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    Jun 22, 2012
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    Do you mean Capacitors as used in fluorescent lighting and motors?
     
  4. kubeek

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  5. PatM

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  6. DerStrom8

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    I think the OP is actually referring to the ferrite "bead" clips that clip over power cords:

    http://en.wikipedia.org/wiki/Ferrite_bead

    The are usually used on the DC side of AC-DC power supplies. So that should answer the OP's question, if that is in fact what he's referring to.

    Matt
     
  7. wmodavis

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    Oct 23, 2010
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    I think he is referring to pop cans. If over stressed they go POP!
     
  8. ErnieM

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    Apr 24, 2011
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    Might be the ceramic insulators.
     
  9. GopherT

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    Nov 23, 2012
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    The OP could be asking about these cylinders but he seems to have vanished...
     
  10. dthx

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    May 2, 2013
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    yeah....I think he meant those....on telephone poles....
    transformers right....?...stepping the voltage down....right?
     
  11. THE_RB

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    Feb 11, 2008
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    No, he would hardly be asking about using "pole pigs" in his DC circuit.

    The likely device would be those cylindrical ferrite suppressor beads they use in PC power supplies and appliances for common mode noise/spike suppression.
     
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  12. atferrari

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    He found a way to create suspense.

    Will he come back?

    Will he tell us what those things are?
     
  13. GopherT

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    Thanks, that was my point. I know he wasn't talking about pole transformers (I hope he wasn't), but we all keep guessing even though he is not coming back.
     
  14. tubeguy

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    Nov 3, 2012
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    Yep. Those are transformers. We had one near our house explode during a storm. You can imagine...
     
  15. DerStrom8

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    You don't even know what the OP was asking about, how do you know they're transformers? :rolleyes::p

    We still need the OP to post a photo.
     
  16. YokoTsuno

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    Jan 1, 2013
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    I assume you mean these things: http://en.wikipedia.org/wiki/Ferrite_bead

    These are used to increase what is called the common mode impedance of the power cord. This:
    -Attenuates part of the EMI (the one with reference to earth) generated by the device and therefore prevents it from spreading further via the power lines.
    - Reduces the device's sensitivity to external EMI.

    Yes, these things can also be used for DC, In fact they are, since you often see them at the DC side of notebook adapters.

    They often provide an easy work-around for circuits that would not pass EMI standards without spending months of attempts to change circuit lay-out.
     
  17. DerStrom8

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  18. YokoTsuno

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    Jan 1, 2013
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    Probably need spectacles :D
     
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  19. DerStrom8

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    Feb 20, 2011
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    Yup, same here :p
     
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