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Homework Help: Find the equivalent resistance seen by the source

  1. Jun 25, 2012 #1
    1. The problem statement, all variables and given/known data


    a) the equivalent resistor seen by the source;
    b) value of i0;
    c) value of v;
    d) value of v0.

    http://img823.imageshack.us/img823/4406/dasso.jpg [Broken]

    2. Relevant equations

    Kirchoff's laws and Ohm's laws

    3. The attempt at a solution

    To solve b,c,d I need to get a right which I didn't. I got 6Ω for the equivalent resistor and the right answer is 8Ω. I don't understand why!
    Isn't the circuit made of those 36Ω and 44Ω in series and the 40Ω,10Ω,30Ω in series and the paralel of those with the rest? I don't get why I got it wrong.

    Can you people help me?
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Jun 25, 2012 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Hello scanferr. Welcome to PF !

    [STRIKE]I also get 8Ω for the equivalent resistance.[/STRIKE]

    Show how you got your answer.

    Added in Edit:

    Actually, I also get 6Ω .

    I don't know why I initially wrote 8Ω .
    Last edited by a moderator: May 6, 2017
  4. Jun 25, 2012 #3
    I got 6 ohm as my answer !
  5. Jun 25, 2012 #4


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    Staff: Mentor

    6 ohms here, too. How can we all be using the same buggy calculator? :wink:
  6. Jun 26, 2012 #5


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    Science Advisor

    I get 6 ohms too. 8 ohms is just wrong. It happens.

    Anyway, you would then calculate the voltage between the top and bottom supply rails and calculate the currents through the parallel resistors and networks.

    V = I * R. I = 8 amps. R = 6 ohms.
  7. Jun 29, 2012 #6
    Thanks guys!

    It seems the solution is wrong then. It happens yes, and I was kinda confused because I didn't know how 8ohms could be right!
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