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Homework Help: Calculate the resistance in the circuit

  1. Dec 22, 2017 #1
    1. The problem statement, all variables and given/known data
    All resistors are ## R = 10 \Omega##
    2. Relevant equations
    Calculate the total Resistance

    3. The attempt at a solution
    all resistors are parallel, so
    $$ \dfrac{1}{R_{AB}} = \dfrac{1}{R} + \dfrac{1}{R} + \dfrac{1}{R} + \dfrac{1}{R} + \dfrac{1}{R} + \dfrac{1}{R} $$
    ## R_{AB} = \dfrac{R}{6}##
  2. jcsd
  3. Dec 22, 2017 #2


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    Why do you think they are all in parallel? They arent, for example R2 and R3 are in series.

    Hint: The circuit has some symmetry. If you applied a voltage to AB what would be the voltage across R6?
  4. Dec 22, 2017 #3


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    Look up 'balanced Wheatstone bridge'.
  5. Dec 22, 2017 #4


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    As has already been pointed out, this is incorrect. I strongly suggest that you review, several times, the definitions of serial and parallel. Until you have those down cold, you will continue to have problems with circuit analysis.
  6. Dec 23, 2017 #5
    Since no current will flow through R6 you may delete it [R6].
  7. Dec 28, 2017 #6


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    As @Babadag stated, you can ignore R6. But suppose it was not balanced (or you didn't recognize that). You could do a delta-Y transformation with R2 R4 & R6, to simplify things, if you have learned that.
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