Simple circuit analysis Q

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• Jun 21st 2011, 11:24 PM
Glitch
Simple circuit analysis Q
The question
http://i.imgur.com/XWLrV.png

I want to find the node voltages via KCL.

I seem to have forgotten what to do when there's a resistor in series with a voltage source. e.g. with node v3, to find the current entering the node from the lower branch, normally I'd use V/R (i.e. v3/5). However there's a 1v voltage source on the branch. How do I work with that?

Thanks.
• Jun 22nd 2011, 02:39 AM
Ackbeet
Re: Simple circuit analysis Q
Quote:

Originally Posted by Glitch
The question
http://i.imgur.com/XWLrV.png

I want to find the node voltages via KCL.

I seem to have forgotten what to do when there's a resistor in series with a voltage source. e.g. with node v3, to find the current entering the node from the lower branch, normally I'd use V/R (i.e. v3/5). However there's a 1v voltage source on the branch. How do I work with that?

Thanks.

The short answer is that it's another node. Basically, you need two more nodes: one between the 2V source and the 1 ohm resistor with i6 going through it, and another one between 5 ohm resistor with i5 going through it and the 1V source.

Incidentally, don't forget to use supernodes for your dependent sources. Come to think of it, that may be the best technique for handling those voltage sources anyway.
• Jun 22nd 2011, 02:41 AM
Glitch
Re: Simple circuit analysis Q
Thanks!
• Jun 22nd 2011, 03:10 AM
Ackbeet
Re: Simple circuit analysis Q
You're welcome. If you have any further difficulties, let us know.