Nodal Analysis and Power consumption

Discussion in 'Homework Help' started by Intrud3r, Mar 9, 2009.

  1. Intrud3r

    Thread Starter New Member

    Mar 9, 2009
    Hi, i've been posed the following question:


    From nodal anlysis i obtained v1=15 v2=v=5 v3=-20

    Does that mean v3 is supplying the voltage through the circuit?!? Also could you check to see if those values are correct.

    Also how am i supposed to be able to calculate the power associated with the dependant power source. Does the - value mean it is being delivered to the circuit and that and that the 15V power source is actually absorbing the power?

    for part c) is the power value 37.5W, and is it being delivered? as it is a positive value?

    Any insight into this problem would be much appreciated. Also what is the answers to each section, a) b) c) etc. as i am absolutely stumped.

    Thomas Introna
  2. hgmjr

    Retired Moderator

    Jan 28, 2005
    If you calculated v = 5, shouldn't the dependent voltage source be 5*v which equals 25 volts?

  3. vvkannan

    Active Member

    Aug 9, 2008
    Hi Intrud3r,
    I get the same values as you have got .

    Now you know all the voltages (hence the current)

    Calculate the power across the resistors and add them

    Calculate the power across 15 v source.(15 x 2).
    This is less than the power drawn by resistors. Hence the dependent source supplies the remaining power