1. Not finding help here? Sign up for a free 30min 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!

Help solving Circuit

  1. Feb 8, 2014 #1
    ImageUploadedByPhysics Forums1391875387.022416.jpg

    The question asks to find the Equivalent resistance R(ab) for the circuit. Is this a trick question? Because I thought it is an open circuit and therefore the resistance between a and b would be infinite. The answer in the book is 20 ohms, please explain if possible
     
  2. jcsd
  3. Feb 8, 2014 #2

    AlephZero

    User Avatar
    Science Advisor
    Homework Helper

    Why do you think the resistance is infinite? There are lots of ways the current can flow from a to b.

    You can solve this by picking off pairs of resistors that are in series and parallel, and replacing then with a single resistor. You will end up with just one resistor connecting a and b.
     
  4. Feb 8, 2014 #3
    Because there is no wire connecting points A and B I thought this is an open circuit, which has infinite resistance?
     
  5. Feb 8, 2014 #4
    ImageUploadedByPhysics Forums1391880549.364392.jpg

    This is my final step in reducing the circuit, so now this makes sense that the resistance would be 20, I kept thinking that current would not flow flow from a down to b because they were separated but they are connected
     
  6. Feb 8, 2014 #5

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Moderator's note: thread moved from Electrical Engineering.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted