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Anonymous Poster #1

Source Conversion

08/05/2011 11:28 AM

The current to voltage conversion as sub calculation is done to find branch current in super-position theorem.But the total load current is additive in normal procedure but subtractive in the source converted method.If you understand my question give a solution.

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#1

Re: Source conversion

08/05/2011 11:36 AM

Is that an order or a request?

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#2

Re: Source conversion

08/05/2011 11:36 AM

Question, what question? I see a confusingly phrased partial understanding of Kirchoff's current and voltage laws but I do not see a question. A question should be punctuated by a question mark (?).

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#3

Re: Source conversion

08/05/2011 11:46 AM

Why would you perform a current to voltage conversion to find the current in a branch?

If the total load current is found using an additive method, why use a subtractive method using a converted algorithmic solution from a problem that started with a solution?

Those are questions which you have already answered, as you worked backwards from the solution to begin with.

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#4

Re: Source Conversion

08/06/2011 1:26 AM

Do you even understand your own "question"? If so, please explain.

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Anonymous Poster #1
#5
In reply to #4

Re: Source Conversion

08/06/2011 3:53 AM

My friend solved a circuit with 2 current source by converting one current source into voltage source. I did by open circuit of one current source and following superposition theorem. So I got 2 currents and the total load current is additive as i got both positive and flows in same direction via load. But when by friend did it he got currents flowing opposite via load. Does source conversion advised in superposition theorem?

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#6
In reply to #5

Re: Source Conversion

08/06/2011 4:37 AM

That was incomprehensible. Please try again.

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#7
In reply to #5

Re: Source Conversion

08/06/2011 8:19 AM

From your fractured description I cannot grasp with certainty what you or your friend have done. So I can only guess at where an error has happened.

It is very easy in doing a superposition analysis of a circuit to make a simple error in your initial loop and mesh equations. A common confusion can happen when the current directions are initially established that a subtraction instead of an addition should be part of the initial equations. Now when an error like this happens, one can only find the error by examining the actual steps taken.

Another plausible error is that the transformation of a source from a current to voltage source forgot to include the source impedance.

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Anonymous Poster #1
#8
In reply to #7

Re: Source Conversion

08/06/2011 9:27 AM

No the source impedance is included.I didnt say any change in magnitude of current but direction. Can you please do it in a paper and verify?

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#9
In reply to #8

Re: Source Conversion

08/06/2011 10:04 AM

Me? Why should I put anything down on paper when it is you and your friend who some how mysteriously come up with different answers. If anyone should post their answer its you.

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#10
In reply to #9

Re: Source Conversion

08/06/2011 10:34 AM

hahaha

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Anonymous Poster #1
#11
In reply to #9

Re: Source Conversion

08/06/2011 11:20 AM

Assume a 20V source with internal resistance 2ohms,10A current source and a 3ohms resistor are connected in parallel. By super position theorem I got 4A downwards across load resistance due to 20V source and 2A downwards due to current source(10A) via load(3 ohms). So total load current =4+2=6A. Now my friend got 4A downwards as me and he converted 10A current source to 20V voltage source so he got second current of 2A flowing opposite to 4A.So his total load current is 4-2=2A :( please help here.

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#12
In reply to #11

Re: Source Conversion

08/06/2011 10:59 PM

Now what was the source impedance for the current source? Tell your friend to carefully review the sign of the currents their calculating. Just examine the current numbers using KCL. 4A+6A=10A 4A+2A=6A≠10A

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Anonymous Poster #1
#13
In reply to #12

Re: Source Conversion

08/06/2011 11:46 PM

But the direction of current is correct in all aspects because the converted voltage source is opposing the current from the first voltage source.

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#14
In reply to #13

Re: Source Conversion

08/06/2011 11:49 PM

You can lead a horse to water, but you cannot make them drink.

I cannot force you to think for yourself.

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Anonymous Poster #1
#15
In reply to #14

Re: Source Conversion

08/07/2011 2:11 AM

Thank you

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