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Equivalent resistance of simple circuit

  1. Sep 18, 2013 #1
    1. The problem statement, all variables and given/known data
    Find the equivalent resistance of the following circuit.
    http://img706.imageshack.us/img706/9644/zkz7.png [Broken]

    2. Relevant equations

    3. The attempt at a solution
    I am not able to find out which are resistors are in series and are in parallel.Is there any special method to solve these problems?
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Sep 18, 2013 #2
    Think about drawing this in a different way so you can see the parallel and series resistors more clearly
  4. Sep 18, 2013 #3
    Use the symmetry of the circuit. There is a plane about which the circuit is symmetrical. By symmetry all the points in this plane are equipotential. Armed with this information you can simplify this circuit by removing a resistor as no current flows through it.
  5. Sep 18, 2013 #4
    thanks a lot!!:thumbs:
    i solved the problem
  6. Sep 18, 2013 #5


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    Science Advisor
    Gold Member

    This network is an example of non-parallel/non-serial. The direct method is to use the Y-Delta transforms: http://en.wikipedia.org/wiki/Y-Δ_transform

    Then you can slowly reduce the network to a single resistance. The symmetry argument is very clever ... but the transforms work even when you are not feeling clever!
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