# Homework Help: Mesh Analysis

1. Feb 18, 2014

### Maylis

1. The problem statement, all variables and given/known data
Consider the circuit shown below.
(a) How many extraordinary nodes does it have?
(b) How many independent meshes does it have?
(c) The values of how many of those mesh currents can be determined immediately from the circuit?
(d) Apply mesh analysis to find I’.

2. Relevant equations

3. The attempt at a solution
I am having a hard time for parts (a) and (b). I put a dot on everything I called an extraordinary node, and got 5. My friend got 10 and I don't see it.

Also, the the independent meshes, apparently where the 7 Amp current source is, you can't say the furthest right branches mesh current by inspection. How is this?

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2. Feb 19, 2014

### Staff: Mentor

What is the definition of an extraordiary node?

3. Feb 19, 2014

### Maylis

Where 3 or more junctions meet

4. Feb 19, 2014

### Staff: Mentor

That is too ambiguous, too imprecise. What is the formal definition from your course notes?

5. Feb 19, 2014

### The Electrician

6. Feb 19, 2014

### Staff: Mentor

You were probably told that so as to contrast it with most of the other meshes in this figure. Most meshes here show a current source in one of their unshared branches, and this current sets that mesh's mesh current. The right-most mesh has a current source but located in a shared branch, so that source represents the nett result of two mesh currents, not one current alone.

To say that the mesh current there can't be determined by inpection is arguable, though.

Last edited: Feb 19, 2014
7. Feb 19, 2014

### Staff: Mentor

8. Feb 19, 2014

### Maylis

Given in lecture slide:

Extraordinary
Node:
connection point between at least 3 branches

I watched a youtube video, and now after watching it

I count 8 extraordinary nodes. Anyone else get the same?

Last edited by a moderator: Sep 25, 2014
9. Feb 19, 2014

### Staff: Mentor

8 is the number I count.

10. Feb 19, 2014

### Maylis

Okay great, I feel more comfortable with it now. Thanks