op amp question

Discussion in 'Homework Help' started by zbirdofparadise, Nov 14, 2010.

  1. zbirdofparadise

    Thread Starter New Member

    Nov 14, 2010
    1
    0
    Hi all

    so here is the question (i'm really n00b at this...)

    [​IMG]

    and here is my working out

    .. v3 is that pink dot i forgot to label.

    (va - v0) / 10 000 + (va - v3) / 20000

    then at v3
    2 + (va-v3)/ 20000 = (v3-v0)10000 + v3/ 5000

    whereby va= vb = 0

    i got a really astronomical v0= 2.5 kV

    seems wrong\, though my algebra is shoddy, i'm tiured.. and i sense that, that resistor is just a distraction?????? ahhhh
    thank you
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    You got your currents wrong. Sum all the currents at the pink node (KCL) and assume that Va=Vb=0V.
     
    zbirdofparadise likes this.
Loading...