Analyzing Circuit Nodes & Meshes: Find I'”

[gfd43tg]

Homework Statement

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’.

Homework Equations

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?

 

[NascentOxygen]

What is the definition of an extraordiary node?

 

[gfd43tg]

Where 3 or more junctions meet

 

[NascentOxygen]

Where 3 or more junctions meet

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

 

[The Electrician]

What is the definition of an extraordiary node?

I think it's the same as an essential node:

http://www.tutapoint.com/knowledge-center/view/finding-essential-or-reference-nodes/

 

[NascentOxygen]

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?

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.

 

[NascentOxygen]

I think it's the same as an essential node:

http://www.tutapoint.com/knowledge-center/view/finding-essential-or-reference-nodes/

You're probably right. But I'd like to hear the definition the OP is working with, to understand its apparent shortcomng.

 

[gfd43tg]

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?

 

[NascentOxygen]

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

8 is the number I count.

 

[gfd43tg]

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