need help on superposition prob.

Discussion in 'Homework Help' started by Earless, Oct 1, 2007.

  1. Earless

    Thread Starter Member

    Aug 23, 2007
    11
    0
    Use superposition to obtain the voltage across each current source.

    [​IMG][/IMG]

    I found the partial voltages v1 & v2 due to the 2A current source(shutting off the indep. voltage source), but i cant get the partial voltages due to the 3V voltage source(shutting of the indep. current source) can someone help!!
     
  2. Earless

    Thread Starter Member

    Aug 23, 2007
    11
    0
    What im asking is how do i find V1 and V2 if the circuit looked like this:

    [​IMG][/IMG]

    Ive tried mesh and nodal analysis but keep getting the wrong answer, im confused on what to doo with the loop on the far left.
     
  3. AlexK

    Active Member

    May 23, 2007
    34
    0
    When using the superposition method you short circuit the independent
    voltage sources and you CUTOFF the independent current sources.
    Which means that you have an extra unneeded branch in the second circuit you showed.
     
  4. Kango

    Active Member

    Sep 22, 2007
    30
    0
    Can´t you just do a node analysis? :confused:
     
  5. pinnacle06

    Member

    Feb 9, 2007
    16
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    this is correct... the short you have drawn should be an open
     
  6. Earless

    Thread Starter Member

    Aug 23, 2007
    11
    0
    Is this how the circuit should look?

    [​IMG][/IMG]

    When i try to do nodal analysis what do i do with the 3v source?How do i incorporate it in my nodal equations?
     
  7. Earless

    Thread Starter Member

    Aug 23, 2007
    11
    0
    Ok i figured it out, i was doing my mesh currents all wrong!, Thnx for your replies!!
     
  8. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    So what were the values you obtained for V1 and V2?

    hgmjr
     
  9. Earless

    Thread Starter Member

    Aug 23, 2007
    11
    0
    V1=1.967V and V2= -.0246, the mistake i made was i thought the mesh current i was the same as the current thru the 5 ohm resistor, so my equations were wrong.
     
  10. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    I don't get the values you calculated. Can you provide a scan of your handwritten calculations?

    hgmjr
     
  11. Earless

    Thread Starter Member

    Aug 23, 2007
    11
    0
    The answers i got agree with the textbook solutions.

    [​IMG][/IMG]
     
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