Rectangular coil calculation

Discussion in 'General Electronics Chat' started by upand_at_them, Aug 19, 2016.

  1. upand_at_them

    Thread Starter Active Member

    May 15, 2010
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    For my own education/entertainment, I'm interested in building a RFID reader. But I'm having a problem with a reference to the formula for a rectangular inductor.

    This page: https://courses.cit.cornell.edu/ee476/FinalProjects/s2006/cjr37/Website/index.htm

    ...refers to a variable "b", which is defined as "the width across the conducting part of the coil". I don't understand what that means, since the entire coil conducts. And I couldn't glean the information from that page as their value of 0.3 cm doesn't seem obvious in any of their pictures. What am I missing?
     
  2. OBW0549

    Well-Known Member

    Mar 2, 2015
    1,301
    880
    I think the "b" parameter is simply the thickness of the bundle of wires in your coil.
     
  3. upand_at_them

    Thread Starter Active Member

    May 15, 2010
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    I'm pretty sure the thickness of the bundle of wires is represented by variable "h", "the height of the coil". "b" seems to be something else.
     
  4. upand_at_them

    Thread Starter Active Member

    May 15, 2010
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    Great, thanks! Sorry, OBW, if that's that you were referring to. It didn't hit me right away that the bundle has two thicknesses.
     
  5. DGElder

    Member

    Apr 3, 2016
    344
    85
    If you laid the coil flat on a table, b (T in the formula below) would be the height. h is the thickness or width of the bundle. The linked blurb with drawing gives a clear definition.

    Formula units are microhenries and inches.

    upload_2016-8-19_21-59-59.png

    upload_2016-8-19_22-0-50.png




    https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwihhKmX8c7OAhWGMSYKHZYVAr8QFgghMAE&url=http://www.minco.com/~/media/Files/Minco/Instructions/Flex%20Circuits/Technical-Specification-FC01.ashx&usg=AFQjCNHKUUHgGN8YZAVNcq9TLrGvTbYYPw&sig2=PiO_kAOiU6iFErG92gtMDQ
     
    Last edited: Aug 19, 2016
  6. upand_at_them

    Thread Starter Active Member

    May 15, 2010
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    :thumbs up:
     
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