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Homework Help: Finding Resistance

  1. Mar 28, 2008 #1
    [SOLVED] Finding Resistance

    1. The problem statement, all variables and given/known data
    A number of resistors of values R1 = 3.8 Ω, R2 = 80.0 Ω, and R3 = 20.0 Ω are connected as shown in the figure. What is the resistance between points A and B?


    2. Relevant equations



    3. The attempt at a solution

    Im confused because all I've been calculating is the equivalent resistance, what is the difference between the two?
     

    Attached Files:

  2. jcsd
  3. Mar 28, 2008 #2

    berkeman

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    Staff: Mentor


    They are just asking for the equivalent resistance of that network, as seen at the entry points A & B. Just use your series & parallel combination rules to reduce the network to a single (equivalent) resistor between A & B, and you will have your answer.
     
  4. Mar 28, 2008 #3
    ok thank-you
     
  5. Mar 28, 2008 #4
    The Four R1 and R3 are in series thus those five resistors to the right can be combined by adding the value....(4*3.8+20)=35.2Ω
    That resistance is in parallel with the R2 thus the combination of the five and this resistor is equal to 1/(1/35.2+1/80) = 24.4Ω (3sf)
    Now the total becomes this plus 2*R1

    Total = 24.4+3.8*2 = 32.0Ω (3s.f.)

    Just incase you were still stuck, that and I like to go back to some easy electronics now and again to remind me that my head hasn't exploded :)
     
  6. Mar 29, 2008 #5
    You shouldn't give out the answers. We're not here to give solutions, but rather how to figure out a problem.
     
  7. Mar 29, 2008 #6
    My Apologies, I was only going from what I saw in the rest of the forum.
     
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