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: Kirchhoff's Current Law (easy!)

  1. Sep 26, 2010 #1
    1. The problem statement, all variables and given/known data

    [PLAIN]http://img24.imageshack.us/img24/4168/circuitv.png [Broken]

    Find vx and ix.


    2. Relevant equations

    Kirchhoff's Current Law: The algebraic sum of the currents entering a node is zero at any instant:

    Σi = i1 + i2 +... iN = 0

    3. The attempt at a solution
    Since it's a current-driven circuit and ix points in the opposite direction of is,

    ix = -is, where "is" is the current source.

    We know that is = 2 mA, so... ix = -2 mA

    ... and vx = ixR
    so vx = (-2 mA)(47 k ohms) = -94V

    Is this right?
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Sep 26, 2010 #2

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Yes, that looks good.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook