# Nodal Analysis

Discussion in 'Homework Help' started by Chupa, Apr 5, 2008.

1. ### Chupa Thread Starter New Member

Mar 27, 2008
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Hey I'm back! A quick thanks to veritas for all his help last time!

Now I'm doing my Nodal Analysis lectures.

So far I've managed to answer everything on the problem sheet but one.

Interestingly, I can attain the correct answer for this problem using superposition (so I suppose the circuit is correct). However, nodal analysis (involving by-inspection followed by Gaussian Elimination) isn't working or I'm doing something wrong.

The question I'm stuck on is #8.

Thanks in advance! ^_^

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2. ### hgmjr Retired Moderator

Jan 28, 2005
9,029
219
Can you supply us with the results of your efforts thus far?

hgmjr

3. ### guitarguy12387 Active Member

Apr 10, 2008
359
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You should be alright if you apply KCL at a supernode around the 6v voltage source.

4. ### VVS Active Member

Jul 22, 2007
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@ chupa

hey r u also studying ISE or EEE in Imperial College this year??
I have got exactly the same problem and worked it out.

5. ### hgmjr Retired Moderator

Jan 28, 2005
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219
Greetings Chupa,

Did you eventually sort this one out on your own?

hgmjr

6. ### Chupa Thread Starter New Member

Mar 27, 2008
7
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@ VVS: Yes indeed I am! I got stuck on this (and other questions) during revision and this forum came in superbly useful! I was very ill for the past week so I missed on a lot of revision

@hgmjr: I'm actually gonna sit down to this sometime today and see if I can solve it. If not, I know where to ask hehe.

7. ### Chupa Thread Starter New Member

Mar 27, 2008
7
0
I did it! Thanks to guitarguy's advice on utilising the floating Vsource as a supernode, I was able to attain the correct answer.

It seems that the lecture notes' method of removing the voltage source and then reapplying it is quite clunky.

In the text book, it also performs the same operations by considering the floating Vsource(s) as a supernode. When you remove and re-add the source, the objective is to combine or add the matrix -rows corresponding to either end of the Vsource. This effect is realised instantaneously with the supernode method it seems.

8. ### hgmjr Retired Moderator

Jan 28, 2005
9,029
219
In case you are interested, the application of Millman's Theorem to this problem results in a fairly compact solution.

hgmjr

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