Help me in finding error in maxwell theorem

Discussion in 'General Electronics Chat' started by aamirali, Jul 12, 2014.

  1. aamirali

    Thread Starter Member

    Feb 2, 2012
    415
    1
    I have attached a circuit.
    I have to measure voltage across load. I have used maxwell method to solve this.

    Problem is voltage across load comes out to be negative since current I2 that I have calculated comes out to be negative.

    However while simulation in multisim result is positive voltage.
    However magnitude is same in both case but I get error in sign.

    I don't know where I am doing error?
     
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  2. wayneh

    Expert

    Sep 9, 2010
    12,093
    3,032
    You got the sign wrong in the last step on the left hand side, where the two separate equations are added or subtracted.
     
  3. aamirali

    Thread Starter Member

    Feb 2, 2012
    415
    1
    couldn't find??
     
  4. wayneh

    Expert

    Sep 9, 2010
    12,093
    3,032
    My mistake. I tried to follow your work and thought I had spotted the problem, but I've missed it.

    The problem HAS to be in (2), since it shows the sum of zero for two physical quantities we know are both positive. I think the node voltage at the start is wrong.
     
  5. Brownout

    Well-Known Member

    Jan 10, 2012
    2,375
    998
    You have a division problem in your first box, and you have an addition problem in your second box. I didn't look further.


    Edit: the division problem in your first box did not propagate to your final solution. So it is inconsequential.
     
  6. aamirali

    Thread Starter Member

    Feb 2, 2012
    415
    1
    any help????
     
  7. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    How much help do you expect?
    First of all, your handwriting is barely legible, so no wonder people dont bother reading your equations.
    Second, did you correct what Brownout suggested? What was the result?
     
  8. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,516
    1,247
    Starting at the load and working backwards toward the battery, you have two resistors in series, in parallel ith another resistor, in series with another resistor. Ohm's Law all the way to the battery current, then work forwards toward the load to get the voltage across each resistor.

    ak
     
  9. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
    428
    isnt this more of Kirchoff formulas? series and paralell resistances?
    Maxwells formulas have been proven for many years, why do you think you have found a problem now?
     
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