Help in a circuit

Discussion in 'Homework Help' started by luigihs, Oct 10, 2012.

  1. luigihs

    Thread Starter New Member

    Oct 10, 2012
    12
    0
    Hi Im trying to figure this circuit
    [​IMG]

    I already got the total current that I did doing the Delta / star . what I got is 4.06 for total current, now is asking me to get the current of R1 , I know I have to get the voltage in order to get the current that is I = V/R but I dont have any idea how to get the voltage when is parallel im lost somebody can help me please! :(
     
  2. luigihs

    Thread Starter New Member

    Oct 10, 2012
    12
    0
    Anyone :( ?
     
  3. justtrying

    Active Member

    Mar 9, 2011
    329
    347
    the calculations for this circuit work out very nicely. You should get a round number for your total current, from there on, if you are using conversion, you have to work backwards to calculate currents through the legs. Current divider rule is handy. I think that mesh analysis is easier when solving these problems when they are not so nicely set up.

    1. you may have made a slight mistake during conversion, as I total is slightly off
    2. apply current divider to figure out current through R1
     
  4. mlog

    Member

    Feb 11, 2012
    276
    36
    This problem screams, "Use mesh analysis!"
     
  5. WBahn

    Moderator

    Mar 31, 2012
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    I agree -- mesh current is the way to go. Doing the delta-wye transforms is valid and will work, but I think the effort involved in doing the transformations (plus the resulting parallel reductions that follow) is more than the effort of doing the mesh current analysis, especially since the latter will yield the information you need to answer the follow-up questions directly.
     
  6. justtrying

    Active Member

    Mar 9, 2011
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    347
    These problems are definitely to be solved by mesh analysis - simple and effective - but I have a feeling that the OP has not been exposed to it yet...
     
  7. WBahn

    Moderator

    Mar 31, 2012
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    Then hopefully the OP will say so and we can find out what the relevant background is and go from there. But I know that I got mesh, nodal, superposition, and source transformations before I got delta-wye conversions.
     
  8. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,974
    744
    Total resistance is, 1R in parallel with 5.5R = 0.846R

    so total resistance is 2.4R+2R+0.846R=5.24R

    voltage drop across R1= 0.846/5.24 X 16V =2.58V

    so current is 2.58Amps
     
    Last edited: Oct 13, 2012
  9. The Electrician

    AAC Fanatic!

    Oct 9, 2007
    2,281
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    You have ignored the effect of the 3Ω resistor.
     
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