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A homework in Direct Circuit for beginning students

1. Homework Statement

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2. Homework Equations

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3. The Attempt at a Solution

Well, I am not familiar with the Latex system on this website, just because I am a newbie and I rarely access to this forum. I have a problem (may be simple for you guys) but I still need a solution from you, or at least, please give me the answer if you are boring with typing a lot of formulae.
Thank you in advance
 

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Thanks naspook
I did have the solution that was solved by myself, and I think it's suitable for pupils, not a student but one day, my little brother gave a solution that was different to mine, and he believes that my solution is not right, So I need an answer from you to check.
 

nsaspook

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So I need an answer from you to check.
Why don't you give your answer and the steps you took to find your results first in the proper format for this forum.
 

phinds

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... please give me the answer
You need to read the forum rules. We help folks figure out how to solve problems, we do NOT just "give answers".
 
Why don't you give your answer and the steps you took to find your results first in the proper format for this forum.
Yeah, my steps: this DC circuit is a familiar one and we only need to know that with the given assumption as the ammeter is ideal, the potential difference between two points of [itex]\ R_5[/itex] is zero, then as a consequence [itex]\ {I_5}=0A[/itex]. And [itex]\ {I_1}=2A[/itex], [itex]\ {I_2}=2A[/itex],[itex]\ {I_3}={I_4}=1A[/itex], then from Kirchooff law, [itex]\ {I_A}=4A[/itex].
Net resistance of the circuit is [itex]\ {R_{AB}}=6Ω[/itex]
 

BvU

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Yeah, well, you sure take big steps. Especially from I5 to I1, 2,3,4. Perhaps you want to explain the 2,2,1,1 in a little more detail ? And: what did your young brother find ?
 
to BvU:
Well, this problem can be solved simply by re-draw the circuit with the rule as: Consider all points that have the equal potential is one. So we can have a new and simple diagram, from it we get I1, I2, I3, I4, and of course, I5=0 as mentioned above. It's my steps

My little brother: I think he did make a small fault when he re-draw the diagram
 

BvU

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Still: what did your young brother find ?

I agree with I5. Also with the two 1. But don't you become suspicious at all when 30 V over 6 Ohm gives 4 A ?
 

nsaspook

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Yeah, my steps: this DC circuit is a familiar one and we only need to know that with the given assumption as the ammeter is ideal, the potential difference between two points of [itex]\ R_5[/itex] is zero, then as a consequence [itex]\ {I_5}=0A[/itex]. And [itex]\ {I_1}=2A[/itex], [itex]\ {I_2}=2A[/itex],[itex]\ {I_3}={I_4}=1A[/itex], then from Kirchooff law, [itex]\ {I_A}=4A[/itex].
Net resistance of the circuit is [itex]\ {R_{AB}}=6Ω[/itex]
Points for trying but you need to review a few things. It's aways good to work backwards (what voltage is across each node with your current calculations) from your result to check for errors.
http://www.usna.edu/Users/cs/vincent/suppnotes/EE301Topic06.pdf [Broken]
 
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Of course, nasaspook, we should review it, but I did knew this theory many years ago when I was in 9-grade class and I did give my answer.
Could anyone give me your numerical answer, that is all I need
 
Could anyone give the answer for me? I need it to check, this problem seems to be simple, but I need the answer from you
 

BvU

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Could anyone give me your numerical answer, that is all I need
Is not the way PF works. You have a choice to ignore answers to questions and hints to improve your work. You can not ask for 'the answer'.
 

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