1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    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!

Node-Voltage help. Is my equation right?

  1. Feb 28, 2010 #1
    1. The problem statement, all variables and given/known data
    Find Voltage V_0. There is also a dependent voltage source in the circuit I'm not sure what to do with.
    The two nodes on top are essential nodes and can be treated as one, same with both bottom nodes, but the bottom nodes I assigned them to be the reference node.

    Picture: http://img696.imageshack.us/img696/5396/1000948x.jpg [Broken]

    2. Relevant equations

    3. The attempt at a solution
    My node voltage equation : -3 + V/200 + (V-5i)/10 + (V -80)/20
    V is V sub 0: V_0
    and i is i sub delta i_Δ

    For the equation for i_Δ : would it be (v-80)/20

    Again I'm unsure of how to handle the dependent source in this circuit.
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Mar 1, 2010 #2


    User Avatar

    Staff: Mentor

    There really is only one KCL equation for that circuit. You write the sum of all the currents leaving (or entering) the node at the upper left of the circuit (you are correct to call the bottom node the reference or ground node). Don't over-think this -- keep thinking currents. So for the right-hand leg, what is the current leaving out that way? Hint: No voltages are involved. Alternately, you can write i_Δ in terms of V_o and constants...
    Last edited by a moderator: May 4, 2017
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook