Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Thevenin equivalent circuit

  1. Sep 4, 2008 #1
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution

    I trying to figure out a thevenin equivalent circuit

    I want to calculate the current I so I cant get the resistance for the thevenin equivalent.

    Im not 100% sure how to calculate I, can I use KCL on the node under the number -8.7V?

    http://img98.imageshack.us/my.php?image=curfc7.jpg
     
    Last edited: Sep 4, 2008
  2. jcsd
  3. Sep 4, 2008 #2

    Defennder

    User Avatar
    Homework Helper

    Re: thevenin

    That sure is a complex circuit. To find Rth, kill all the current and voltage sources and then measure the equivalent resistance between A&B.

    KCL is valid everywhere. Is that -6.7 and -8.7 node voltages given by the question? If so, then you can easily find Isc. Also note that the 1mA source is connected in parallel with a short-circuited wire.
     
  4. Sep 12, 2008 #3
    Re: thevenin

    so if short circuit the system. Can I setup KCL on node A and then solve for I,
    I = I(source) + I(R10).

    But it seems odd to do so.
     
  5. Sep 12, 2008 #4

    Defennder

    User Avatar
    Homework Helper

    Re: thevenin

    You got the equation wrong. It's IR10 = Isource + I. Be careful of the direction designated for Isc.
     
  6. Sep 16, 2008 #5
    Re: thevenin

    ok, got everything together now, ty for the help!
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook