Help me in finding error in maxwell theorem

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

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
12,389
3,245
You got the sign wrong in the last step on the left hand side, where the two separate equations are added or subtracted.

Feb 2, 2012
415
1
couldn't find??

4. wayneh Expert

Sep 9, 2010
12,389
3,245
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.

Feb 2, 2012
415
1
any help????

7. kubeek AAC Fanatic!

Sep 20, 2005
4,689
806
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
4,699
1,298
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?