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Homework Help: Simplifying Resistor Circuits

  1. Oct 13, 2012 #1
    1. The problem statement, all variables and given/known data

    See attached image.

    2. Relevant equations

    3. The attempt at a solution

    I cannot find any resistors in parallel or series in the circuit. I am confused by the lone branch going from the 10kOhm resistor back to the other end of the same resistor. How do I deal with that?
    I tried specifying nodes, Node A being connected to the 10kOhm, 20kOhm and maybe the 30kOhm and 80kOhm resistors? Node B connected to the 8kOhm and the 80kOhm resistors. Node C connected to the 20kOhm, 30kOhm and the 8kOhm resistors.

    This way I get 20kOhm and the 30kOhm resistors in parallel, but then I am confused about how to deal with the 10kOhm resistor. Is it in series? Parallel? with the other 2?

    Attached Files:

  2. jcsd
  3. Oct 13, 2012 #2


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    The 10ohm resistor seems to have been put in just to see if you know what you are doing, since it isn't REALLY in the circuit. Take it out and redraw the circuit and you'll find parallel and then series resistors (after you reduce the parallels)
  4. Oct 13, 2012 #3


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    One way to look at it: the 10kΩ resistor is actually in parallel with a 0Ω resistor (the wire).
  5. Oct 13, 2012 #4
    80Ω//( 8Ω series with (20Ω//30Ω))
    So, equivalent resistor of cirrcuit is 80//(8+12)=16Ω
    10 Ohm resistor is shorted cirrcuit.
  6. Oct 13, 2012 #5


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    Please read the forum rules. It is innappropriate to GIVE the answer. The point of this forum is not to give people the answers to homework problems but to help them learn how to THINK and get their own answers. Give HINTS, not answers.
  7. Oct 13, 2012 #6
    you are right. sorry
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