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!

Physics question circuit and resistance?

  1. Apr 9, 2013 #1
    Find R and build a circuit which has an only current source and an only resistance.
    My attempt :
    Obv I thought about applying Kirchhoff's circuit law.The first one.
    Then I thought about finding the total resistance which from the figure is 1/Re=1/25 +/100 so Re is 20 Ohm.The problem is that for applying K's law I have to find R,but how do I find it?

    IMPORTANT : IN THE FIGURE,THE TENSION IN R IS 30 SINT Volt.
     

    Attached Files:

  2. jcsd
  3. Apr 9, 2013 #2

    gneill

    User Avatar

    Staff: Mentor

    One way to proceed is to combine (simplify) all the items of known values to begin with and redraw the simplified circuit. You've already shown that the two known resistors can be combined into a single resistance of 20Ω. Can you do the same for the current sources? How does the siplified circuit look then?
     
  4. Apr 9, 2013 #3
    That is the point,how do I combine them,with the K's law?
     
  5. Apr 9, 2013 #4

    gneill

    User Avatar

    Staff: Mentor

    KCL at the top and bottom nodes. What are the contributions of the two current sources? Can you represent their contributions with a single source connected to those nodes?
     
  6. Apr 9, 2013 #5
    Why don't you do it for me,consider it an early Thanksgiving present.Life is so hard.Why did I even choose engineering? I should be paid based on my awesomeness :D *sobs and schedules new appointment at the shrink*
     
  7. Apr 9, 2013 #6

    gneill

    User Avatar

    Staff: Mentor

    Alas, this is not a forum where your homework is done for you. We can but offer hints, clarifications, suggestions, and so on, while you must put in the effort and do the work.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted