1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Calculate the equivalent resistance

  1. Feb 1, 2015 #1
    1. The problem statement, all variables and given/known data
    screen_shot_2015-02-01_at_1.34.51_pm.png
    Ignore the internal resistance of the battery and assume it is merely a battery. Calculate the equivalent resistance of the circuit.

    2. Relevant equations
    1/Req = 1/R + 1/R ... (parallel)
    Req = R + R .... (series)

    3. The attempt at a solution
    I know this is fairly simple but I dont understand how you would calculate the equivalent resistance for the three resistors (3.2 ohms, 7.1 ohms, 5.8 ohms). I assumed they were in series and simply added them, and then added 1.0 ohms and 4.5 ohms to get the total resistance. I think this is wrong, can someone explain how you would go about calculating the Req?
     
  2. jcsd
  3. Feb 1, 2015 #2
    I'm afraid you're wrong. All of them aren't in series. See the figure I've uploaded. What can you infer from that? Always deal with 2 resistances at a time. Don't involve 3 together.
     

    Attached Files:

  4. Feb 1, 2015 #3
    I see what you are saying, since 7.1 and 5.8 are in series, they must be added together? And then added in parallel to 3.2?
     
  5. Feb 1, 2015 #4
    You got that right mate!
     
  6. Feb 1, 2015 #5
    thanks!
     
  7. Feb 1, 2015 #6
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted