RTotal?

Discussion in 'Homework Help' started by Celros2, Oct 17, 2012.

  1. Celros2

    Thread Starter New Member

    Oct 11, 2012
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    So I'm looking to find Rt in the circuit attached to the post

    How I went about it:

    4,10= 14 || 4 = 3.33 Ohms

    How Chegg.com went about it:

    4 || 4 = 2, 10 = 12 Ohms


    How do I know that the parallel relationship exists, but the series one does not? I thought I had this stuff down, but the answer really bothered me.


    Thank you in advance.
     
  2. Celros2

    Thread Starter New Member

    Oct 11, 2012
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    Am I doing something wrong? I have like 30 views and no replies.

    If this is too fundamental or something please let me know.
     
  3. The Electrician

    AAC Fanatic!

    Oct 9, 2007
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    How can anybody answer your question when you haven't even shown where Rt is to be measured? Is it across the left pair of terminals? The right pair? Is it across the top pair?
     
  4. catfibres

    New Member

    Oct 17, 2012
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    Good point! If Rt measured across left pair of terminals, = 12 ohms. Right pair = 10 ohms. Top pair = 2 ohms. Bottom pair should be obvious. :D
     
  5. bertus

    Administrator

    Apr 5, 2008
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  6. catfibres

    New Member

    Oct 17, 2012
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    @bertus

    I had not read it at the time. I have now. My apologies for my indiscretions.
    Regards,
    ~catfibres~
     
  7. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    I got Chegg's, 12 Ohm.

    The 4 and 10 Ohm are not in series so you can not add them. The reason they are not in series is because the other 4 Ohm is connected to the junction between 4 and 10 Ohm resistors, forming a "star"/Y of sorts.

    The two 4 Ohm resistors use the same two junctions, so they are in parallel. Their equivalent is 2 Ohm. This equivalent is in series with 10 Ohm. The new equivalent is 12 Ohm, which is also the total resistance of the resistor network, Rt.