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!

Creating Circuits with equivalent resistances

  1. Mar 21, 2013 #1
    1. The problem statement, all variables and given/known data
    Given 4 Identical resistors, I need to be able to find the 9 combinations of circuits with equivalent resistances


    2. Relevant equations
    Do I just keep flipping between parallel resistor sequences?



    3. The attempt at a solution
    I drew 3 different circuits that I believe to be correct, but cannot seem to come up with 9 different ones.
     
  2. jcsd
  3. Mar 21, 2013 #2

    berkeman

    User Avatar

    Staff: Mentor

    Welcome to the PF.

    Could you clarify the problem statement some? What do you mean by "equivalent resistances"? Equivalent to what? To one of the single R values? Or equivalent to some other value, and all 9 combinations are equivalent to that value?
     
  4. Mar 21, 2013 #3
    Maybe I should have typed it word for word... my bad. And thanks for the reply
    You are given for identical 300 ohm resistors. Find as many ways of connecting all four resistors that give unique equivalent resistances. Then my professor gives us a hint that we should get 9 different arrangements using all four resistances that will give unique equivalent resistances.
    Thanks
     
  5. Mar 21, 2013 #4

    berkeman

    User Avatar

    Staff: Mentor

    Oh, unique equivalent resistances. So each configuration will result in a different equivalent resistance, and you have to use all 4 resistors in each configuration. Got it.

    Show us what you have so far, and maybe we can offer some hints...
     
  6. Mar 21, 2013 #5

    berkeman

    User Avatar

    Staff: Mentor

    I'm at 5 right now.... Interesting problem. :smile:
     
  7. Mar 21, 2013 #6

    berkeman

    User Avatar

    Staff: Mentor

    7...
     
  8. Mar 21, 2013 #7

    berkeman

    User Avatar

    Staff: Mentor

    9. :smile:

    How's it going on your end?
     
  9. Mar 21, 2013 #8
  10. Mar 21, 2013 #9

    berkeman

    User Avatar

    Staff: Mentor

    You probably don't have to draw the battery, just show the resistors with the connection points at the ends of the configuration. Unless the problem asks for you to show the battery for some reason.

    So what you have shown so far is:

    4R = R + R + R + R

    R = R/2 + R/2

    Now keep going. Try different combinations and connections, and see if they result in a different equivalent resistance. It's actually kind of fun... :smile:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Creating Circuits with equivalent resistances
Loading...