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Equivalent resistance question

  1. Jan 16, 2014 #1
    (please check attachment)
    Calculate the effective resistance between A and F

    Initially, I thought that the first resistance is ignored and the current takes the lower path. Then 2Ω and 2Ω are in parallel giving an effective resistance of 1Ω.

    However, it could also be that all three are in parallel and thus give an effective resistance of 2/3 Ω.
    If the upper and lower loops are ignored, the resistance is 6Ω!!
    What is the correct answer??
     

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    Last edited: Jan 16, 2014
  2. jcsd
  3. Jan 16, 2014 #2

    tiny-tim

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    hi niktoo1! welcome to pf! :smile:
    hint: wouldn't that only be if the current through BC and CD was flowing the same way? :wink:
    hint: if two points are shown joined by a zero-resistance wire, then they must be at the same potential

    so you can re-draw the diagram omitting the wire completely, and showing those two points as the same point :wink:
     
  4. Jan 16, 2014 #3

    lewando

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    Don't ignore anything. Redraw realizing that A, B, and D are the same node and C, E, and F are also the same.
     
  5. Jan 16, 2014 #4

    phinds

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    attachment.php?attachmentid=65681&stc=1&d=1389875734.jpg
     

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  6. Jan 16, 2014 #5

    Does that mean that each resistor is in parallel with each other?
     
  7. Jan 16, 2014 #6

    tiny-tim

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    what diagram do you get? (mark it with A BD and CE as in the original diagram)
     
  8. Jan 16, 2014 #7

    phinds

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    Which part of post #4 did you not understand?
     
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