Polarized coil?????

Discussion in 'General Electronics Chat' started by spinnaker, Dec 27, 2015.

  1. spinnaker

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  2. ISB123

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    Maybe so that its easier to mount.
     
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  3. spinnaker

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    Good reasoning. Maybe because it is radial and the leads are under the coil it would be harder to mount if the same size??
     
  4. ISB123

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    Yeah,they can just stick the longer lead first and then manipulate the inductor to get the second lead in.
     
  5. ian field

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    That's probably the right answer - but there is such thing as a polarized inductor.

    At one time they were common on CRT TVs. A linearity coil in series with the horizontal scan coils had a magnet associated with it, on VGA monitors the magnet was more usually permanently glued to the inductor core, on TVs with large wide angle deflection CRTs the magnet was usually adjustable by rotating with a trimming tool.
     
  6. SLK001

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    It sometimes is important that the resulting magnetic field is oriented in the right place and polarization. Mount it one way and the polarization is right hand - mount it the other way and the polarization is left hand.
     
  7. GopherT

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    That is crap. That is like saying if I put a nut on one end of a threaded rod I turn to the right, and if I flip the threaded rod I would have to put a nut on it by turning to the left. In reality, a common threaded rod is always righty tighty and lefty loosely.
     
  8. cmartinez

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    Maybe it's just to comply with automated PCB manufacturing equipment requirements?
     
  9. GopherT

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    Yeah, some guy named, Stan, didn't want to bother adjusting the cutter the day that lot was made.
     
  10. cmartinez

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    Gosh... remind me not to invite Stan to the office Christmas party next year... what a moron... :p
     
  11. cmartinez

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    Hey... you replied to my post before I could edit it for clarity... bummer

    EDIT: :mad:
     
    Last edited: Dec 28, 2015
  12. SLK001

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    Sorry, not crap. The magnetic field is determined by the direction of the current thru the coil. Mount it one way and the current goes up the coil. Mount it the other way and the current goes down the coil. And we're talking coils here, not threaded rods - your analogy could not be more wrong.
     
  13. cmartinez

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    The part mentioned is not an electromagnet, but rather an inductor, so it doesn't matter which way the current flows.
     
  14. SLK001

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    What do you think an electromagent is? In some applications, it may not matter which direction the current flows, but this isn't always the case.
     
  15. wayneh

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    An inductor coil can produce a field that interacts with nearby components. So, the polarity of the field can matter. It would make sense to mark it for that reason. I have no idea about the part in question.

    A right hand helix is still right hand if you turn it around, but reversing the leads changes the direction of current flow and thus field polarity.
     
  16. cmartinez

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    I would sincerely like to see an application in a PCB where the orientation of the inductor's field is considered important. Other than for its being used as an electromagnet, of course.
     
  17. spinnaker

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    I would think boards where there are other conductors in close proximity,

    You should have seen the AFC board for the seeker for the Harpoon missile back in the early 80's. All discrete components. The board was about 15cm wide, maybe 30cm length in a half circle. It was so tightly packed with components that you could not see the board. There must have been thousands of components. The rumor is the engineer that designed the board went insane shortly after. I have no idea how they were even able to build such a board let alone repair it.

    I could see magnetic fields being an issue on a board like that.
     
  18. SLK001

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    Build a passive filter. Cross-coupling can kill a filter's response.
     
  19. cmartinez

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    interesting... I have a few inductors laying around, I just might do some experimenting and make some readings with my scope... see what the differences are
     
  20. recklessrog

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