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mesh analysis PROBLEM

djengala

Feb 4, 2016
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hi all im new in electronics and las week i had an exam and a question on the exam was how many meshes are in this circuit http://puu.sh/mUbFA/98ed6b8ad1.png really basic meshes no super meshes or somthinng like that

please help because i think the teacher is wrong thanks in advance
 

Arouse1973

Adam
Dec 18, 2013
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I would have said 4 also. But there must be a reason he said 13?
Adam
 

djengala

Feb 4, 2016
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HERE are the 13 meshes he took
i6CxQp4.jpg
 

Arouse1973

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Well yeah but to work it out I dont think you need all 13. I know a guy that will know all this @Ratch, care to comment?
 

Ratch

Mar 10, 2013
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Well yeah but to work it out I dont think you need all 13. I know a guy that will know all this @Ratch, care to comment?

Depending on the definition of a mesh, I would think that if you can write a KVL equation on it, it is a mesh. For instance, using the above numbering, and selecting loops #9, #5, and #7, one could solve for all the voltages and currents. That is because those three loops cover all the resistors and voltage source. There are other combinations that also cover all the circuit elements.

Ratch
 

Harald Kapp

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Of course you can draw 13 meshes as shown in post #5. This is what the exam asked for, therefore the teacher's answer is correct.
This kind of "test" is a common entertainment.

It is, however, not necessary to identify these 13 meshes and set up the equations for them to solve the circuit, see post #7 by Ratch. This is where you have gotten confused during the exam. In any test, not specifically an electronics exam, it is essential to carefully read and understand the task before answering.
 

djengala

Feb 4, 2016
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Of course you can draw 13 meshes as shown in post #5. This is what the exam asked for, therefore the teacher's answer is correct.
This kind of "test" is a common entertainment.

It is, however, not necessary to identify these 13 meshes and set up the equations for them to solve the circuit, see post #7 by Ratch. This is where you have gotten confused during the exam. In any test, not specifically an electronics exam, it is essential to carefully read and understand the task before answering.

well this kinda sucks because if there is no point in identifying the other meshes then why bother
anyways thanks for all your answers
 
Last edited:

dorke

Jun 20, 2015
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Well,
your teacher is correct.

The definition of a Mesh(in planar circuits) is:
A loop which does not enclose any other loops.
That number here is indeed 13 as shown.

A different question is what is the minimal number of mesh equations needed to "solve" this circuit.
That number here is 1!
Hint:
That circuit can be easily "degraded" to a single mesh (#1) by parallel and serial equivalents of most resistors in it...;)
 
Last edited:

djengala

Feb 4, 2016
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Well,
your teacher is correct.

The definition of a Mesh(in planar circuits) is:
A loop which does not enclose any other loops.
That number here is indeed 13 as shown.

A different question is what is the minimal number of mesh equations needed to "solve" this circuit.
That number here is 1!
Hint:
That circuit can be easily "degraded" to a single mesh (#1) by parallel and serial equivalents of most resistors in it...;)
thank you for the explanation
 
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