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Homework Help: Determining the equivalent resistance of an irreducible network of resistors

  1. Dec 1, 2012 #1
    1. The problem statement, all variables and given/known data

    Alright so I am having trouble finding the equivalent resistance of something like this


    Without "hooking it up" to a current source and solving a large system of equations to find the voltage drop across the network and therefore the resistance.

    Is there a faster way to do this (say in an exam situation)?

    2. Relevant equations

    -kirchoffs laws
    -parallel/series equivalent resistances

    3. The attempt at a solution

    As I described gets me the answer. Want to know if it is the quickest way!
  2. jcsd
  3. Dec 2, 2012 #2


    User Avatar

    Staff: Mentor

    Unless there's a symmetry to exploit with the given values of the resistors (so that the potentials at either end of resistor R3 must be equal), there are two choices:

    1. Add a supply and write three loop or nodal equations and solve

    2. Use a Δ-Y transformation on one of the resistor loops and continue reducing the network
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