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Homework Help: Help solving Circuit

  1. Feb 8, 2014 #1
    ImageUploadedByPhysics Forums1391875387.022416.jpg

    The question asks to find the Equivalent resistance R(ab) for the circuit. Is this a trick question? Because I thought it is an open circuit and therefore the resistance between a and b would be infinite. The answer in the book is 20 ohms, please explain if possible
  2. jcsd
  3. Feb 8, 2014 #2


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    Why do you think the resistance is infinite? There are lots of ways the current can flow from a to b.

    You can solve this by picking off pairs of resistors that are in series and parallel, and replacing then with a single resistor. You will end up with just one resistor connecting a and b.
  4. Feb 8, 2014 #3
    Because there is no wire connecting points A and B I thought this is an open circuit, which has infinite resistance?
  5. Feb 8, 2014 #4
    ImageUploadedByPhysics Forums1391880549.364392.jpg

    This is my final step in reducing the circuit, so now this makes sense that the resistance would be 20, I kept thinking that current would not flow flow from a down to b because they were separated but they are connected
  6. Feb 8, 2014 #5


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    Moderator's note: thread moved from Electrical Engineering.
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