simple problem about nodal analysis

Thread Starter

PG1995

Joined Apr 15, 2011
832
Hi, :)

Almost all the details you will find in the given link below:
http://img171.imageshack.us/img171/9797/nodalysis1.jpghttp://img710.imageshack.us/img710/1565/exampleproblemnodalysis.jpg

You will find the expected (or, target answers) in the top right corner.

As you can see my value for V1 is utterly wrong. It should have been 37.818V according to the answer given in the book. I have checked my equations several times but I found nothing wrong with them. Please help me with it. Many thanks for your help.

Cheers
 

Jony130

Joined Feb 17, 2009
5,599
Your have a error in equation for node V2
I3 = I2 + 2A = V1/4 - V2/4 + 2 = V2/10 this is correct, but after that your simplification is incorrect.
I get this for node 2
5V1 - 7V2 = - 40
 

Thread Starter

PG1995

Joined Apr 15, 2011
832
Thanks a lot, Jony.

V1/4 - V2/4 + 2 = V2/10


I multiplied the above equation by "40". I don't see any error. What am I missing? 10V1 - 10V2 + 80 = 4V2 => 10V1 - 14V2 = -80.

Please guide me. Thanks.
 

Jony130

Joined Feb 17, 2009
5,599
Thanks a lot, Jony.



[/B]I multiplied the above equation by "40". I don't see any error. What am I missing? 10V1 - 10V2 + 80 = 4V2 => 10V1 - 14V2 = -80.

Please guide me. Thanks.
Oops I didn't note this.
So your equation are correct.
I use this site to solve this for me
http://www.wolframalpha.com/input/?i=solve+for+V1++,+3V1+-+2V2+=+48+,+10V1+-+14V2+=+-+80+

And I get
V1 = 416/11 = 37.8181818V

V2 = 360/11 = 32.7272727V

For this equation
3V1 - 2V2 = 48
10V1 - 14V2 = - 80
 

Thread Starter

PG1995

Joined Apr 15, 2011
832
Once again, many thanks Jony.

I made a very silly mistake at the end. While applying Cramer's rule I had incorrectly used "-4" instead of "-14". This was the reason for all the error. I just noticed it now :(. You are really nice.

Best regards
PG
 
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