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Homework Help: Equivalent circuit with resistors neither in series nor parallel

  1. Apr 25, 2009 #1
    1. The problem statement, all variables and given/known data
    all resistors have arbitrary values. the equivalent resistance needs be found between terminal a and b.

    2. Relevant equations
    I have not got a clue how to tackle this problem. as such there is no attempted solution either.

    3. The attempt at a solution

    any help would be great.

    Attached Files:

    Last edited: Apr 25, 2009
  2. jcsd
  3. Apr 25, 2009 #2

    The Electrician

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    Gold Member

    Do you know how to solve a network?

    Have you studied Kirchoff's current and voltage laws?

    Have you studied the mesh, loop, or nodal methods for solving networks?

    We would need to know how far your studies have gone to determine what method would work best for you.
  4. Apr 25, 2009 #3
    I have done Kirchoff's current and voltage laws and their applications in mesh, loop and nodal analysis.

    I'm not sure how they will help with this problem as it is an open-circuit resistance that is being calculated.

    but i could be wrong of course.

    thank you for your reply
  5. Apr 25, 2009 #4

    The Electrician

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    Gold Member

    What you have to do is to add a current source, supplying a current of 1 amp into node a; let node b be your reference node (ground).

    Then solve the network for the voltage at node a. Knowing the current I into node a (1 amp) and the voltage V at node a, the equivalent resistance will be V/I.
    Last edited: Apr 25, 2009
  6. Apr 25, 2009 #5
    yeah, makes sense. I will do it later today as right now i need to sleep.

    thanks for the help.
  7. Apr 25, 2009 #6
    A much simpler way, for me at least, is to use the delta-Y conversion. That way you can use the normal series and parallel connections, without having to resort to KCL and KVL.
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