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Homework Help: Circuit theory question

  1. Oct 31, 2006 #1
    http://img442.imageshack.us/img442/2070/circuit1vf1.gif [Broken]

    i drew this from a superposition question.. the voltage source is shorted out.

    what on earth could Ia be if there's no voltage source?
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Oct 31, 2006 #2
    wow im really stupid. you have to solve for only one voltage/current source at a time, right?

    just out of interest though... is it possible to solve that?
  4. Nov 1, 2006 #3


    User Avatar

    Of course you can solve it by using superposition. Otherwise, you can solve it using Kirchoff's and Ohm's laws.
    Call V1 the voltage between resistors 3 and 5 ohm and V2 the voltage between 5 and 2 ohm. Call ib the current in the 3 ohm resistor and ic in the 2 ohm. You have:
    ib = -V1/3
    ic = V2/2
    ia = (V1 - V2)/5
    ib = ia + 6
    ic = ia + 8
    You have 5 independent equations in 5 unknowns. You can solve it for the unknowns.
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