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Homework Help: Resistance: find the equivalent resistance.

  1. Nov 12, 2012 #1
    1. The problem statement, all variables and given/known data


    2. Relevant equations

    Resistors in series (in a straight line) add. Like R + R = 2R.

    And if in parallel, they inversely add.

    1/R_total = 1/R1 + 1/R2

    So, I have no idea how to "simplify" this.

    Basically trying to find the total resistance.

  2. jcsd
  3. Nov 12, 2012 #2


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    Staff: Mentor

    Start by identifying resistors which are in series or parallel. What do you find?
  4. Nov 12, 2012 #3
    Resistors in series or parallel that could be in series or parallel with others resistors that could be in series and parallel...
  5. Nov 12, 2012 #4


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    Science Advisor
    Homework Helper
    Gold Member

    Start with some pair of resistors that you can analyse without having to consider a third. That could be two in series with no other resistor connected to their junction, or two directly in parallel - i.e. that make a direct connection to each other at each end. Having found such pair, figure out what the effective resistance of the pair is and replace the pair by a single equivalent resistor. Repeat.
  6. Nov 13, 2012 #5
    1) if R=1ohm

    R eq= 2.5ohms

    relation: (2R+R)x(2R+R) / (2R+R) + (2R+R) + R

    2) inverse add last two R, answer will series add with the R in the line, u will eventually see only two R in parallel, then inverse add these last two to get your answer.
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