# node voltage analysis

Discussion in 'Homework Help' started by Hawkeye87, Oct 16, 2008.

1. ### Hawkeye87 Thread Starter Active Member

Oct 7, 2008
52
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ok, i'm stuck on this problem that's due tomorrow morning. I've worked it out and i get stuck right near the end. if anyone could help me i greatly appreciate it. The question says to find the voltage at node A.

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• ###### question 3 text.GIF
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Last edited: Oct 16, 2008
2. ### hgmjr Moderator

Jan 28, 2005
9,030
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It looks like all that you have left is to take your final equation and set it equal to zero and solve for Va.

hgmjr

3. ### Hawkeye87 Thread Starter Active Member

Oct 7, 2008
52
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i've tried that. i factored out a Va and i solve for it and i get a really huge number.

4. ### Hawkeye87 Thread Starter Active Member

Oct 7, 2008
52
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i don't know where to go from there

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5. ### Hawkeye87 Thread Starter Active Member

Oct 7, 2008
52
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well i free handed it and i got something like 1.73 V did anyone get the same thing?

Feb 27, 2008
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7. ### Hawkeye87 Thread Starter Active Member

Oct 7, 2008
52
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does it matter what side the voltage is on? like on mine it was (30-Va)/82, for example.

8. ### hgmjr Moderator

Jan 28, 2005
9,030
214
If you post the steps that you went through to obtain the answer you provided, then we can determine where you went off the rail.

The answer I obtained was 28.308116V.

hgmjr

9. ### alwayslearning Member

Feb 27, 2008
22
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Hawkeye87:

I apparently need to learn the nodal method myself! I saw the answer hgmjr provided; then reworked my solution using mesh analysis (see attachment). I ended up with the same answer as hgmjr:

Va=28.307 volts

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10. ### Hawkeye87 Thread Starter Active Member

Oct 7, 2008
52
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i have an exam one week from today and i have a practice exam that's due wednesday. If i upload it on here could someone guide me through it if i get stuck?

11. ### hgmjr Moderator

Jan 28, 2005
9,030
214
Go ahead and post your problems here in the homework section.

I would strongly encourage you to take a stab at the problems yourself and post what you have done.

If you get us to solve the problems for you without any effort on your part, then we are simply ushering you toward failure. We don't want that and you certainly don't want that.

Working practice problems is the only way to internalize the process. I would not stop with the practice problems. You can find many worked problems on the Internet. I would search for problems that have been solved and work toward understanding how they were done.

hgmjr

12. ### Hawkeye87 Thread Starter Active Member

Oct 7, 2008
52
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would you happen to know of a place that i can find already worked problems that show the steps on how they got the answer?

13. ### hgmjr Moderator

Jan 28, 2005
9,030
214
What type of problems do you need the most exercise on? (e.g. nodal analysis, mesh analysis, kirchhoff's voltage law, kirchhoff's current law, Millman's Theorem, Superposition)

hgmjr

14. ### Hawkeye87 Thread Starter Active Member

Oct 7, 2008
52
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the exam will be covering Superpostion, Thevenins, Branch, Mesh, and Nodal Methods, and that's pretty much it

Jan 28, 2005
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16. ### Hawkeye87 Thread Starter Active Member

Oct 7, 2008
52
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i can't really do much with reading text like that. i'm more of a visual learner and need to see examples myself and see how they worked through the problem and everything.

17. ### hgmjr Moderator

Jan 28, 2005
9,030
214
Go ahead and post your problems with any work you have been able to do thus far.

Then we can see where that takes us.

hgmjr

18. ### Hawkeye87 Thread Starter Active Member

Oct 7, 2008
52
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alrighty. sure will. give me a day or so to work on them an i'll edit this thread with the problems. there are only 4 problems.

19. ### hgmjr Moderator

Jan 28, 2005
9,030
214
We anxiously await the opportunity to assist you with your learning efforts.

hgmjr

20. ### Hawkeye87 Thread Starter Active Member

Oct 7, 2008
52
0
thank you kindly. i'll be working on them tonight and through tomorrow then copy them in here and see if i get the right answers.