# Homework Help: Circuit Nodal voltage question please help out thanks

1. Sep 17, 2007

### engineer_dave

Circuit Nodal voltage question...please help out thanks!!

1. The problem statement, all variables and given/known data
The question is as follows:

Start with KCL for the nodes and write the node voltage equations for the nodes V1 and v2 in the circuit (diagram is attached to this post). They do not want me to solve the equations but just simplify to gather the coefficents.

2. Relevant equations

KCL

3. The attempt at a solution

I marked node one where v1 is. So for node 1 it would be (v1- 30)/10 + (v1-v2)/8 + v1/6=0

I marked node 2 where v2 is. So for node 2 it would be (v2- v1)/8 + (v2+20)/4=0

Still, I am not that sure about my node 2 equations although my node 1 may be correct. Please help! THanks!

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2. Sep 18, 2007

### alvaros

What does KCL mean ?
node 2 is wrong, you forgot 2 Ohms resistor.

3. Sep 18, 2007

### engineer_dave

Can u please elaborate and write down the node 2 equation. Thanks

4. Sep 18, 2007

### engineer_dave

what would be the thing for the 2 ohm resistor then?

5. Sep 19, 2007

### alvaros

(v2- v1)/8 + (v2+20)/4 + v2/2 =0

you didnt answer me:

6. Sep 19, 2007

### malawi_glenn

Kirchoffs law I suppose

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