# nortonization of a simple circuit and nodal analysis

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#### PG1995

##### Full Member level 5
Hi

https://img836.imageshack.us/img836/1554/circuitmm.jpg

1: I was trying to solve a circuit. I was successful except the part where I was trying to apply the nodal analysis (it's at the very end of the linked scan). Where am I going wrong? By nodal analysis I get Isc = 1/3 A which is wrong. Where did I go wrong?

2: How would we proceed while applying nodal analysis if the battery's polarities are reversed?

It would be very nice of you if you could help me with the above queries. Thanks.

Hi
https://img836.imageshack.us/img836/1554/circuitmm.jpg
1: I was trying to solve a circuit. I was successful except the part where I was trying to apply the nodal analysis (it's at the very end of the linked scan). Where am I going wrong? By nodal analysis I get Isc = 1/3 A which is wrong. Where did I go wrong?
You wrote:
2A + I - Isc = 0
2 + (V-12)/4 + (V-0)/16 = 0

2 + (12-V)/4 + (V-0)/16 = 0
....
Final result: V=16 ==> Isc=1

2: How would we proceed while applying nodal analysis if the battery's polarities are reversed?
The same procedure, just open your eyes with the signs.

• PG1995

### PG1995

Points: 2

I should open my eyes too I wrote:
2 + (12-V)/4 + (V-0)/16 = 0​
2 + (12-V)/4 - (V-0)/16 = 0​

Reversing the polarity, would be V=-16 if there were only a voltage source, but here for that, you should reverse the source of 2A too.
-2 + (-12-V)/4 - (V-0)/16 = 0 ==> V=-16​

I should open my eyes too I wrote:
2 + (12-V)/4 + (V-0)/16 = 0​
2 + (12-V)/4 - (V-0)/16 = 0​

Reversing the polarity, would be V=-16 if there were only a voltage source, but here for that, you should reverse the source of 2A too.
-2 + (-12-V)/4 - (V-0)/16 = 0 ==> V=-16​

Hi Eduardo

Actually I should also a bit more careful; I simply copy/pasted your equation.

Sorry, I don't understand the bold part. Could you please explain it a bit? Thank you.

You originally (post #1) wrote:
2 + (V-12)/4 - (V-0)/16 = 0
which, as you know, should be:
2 + (12-V)/4 - (V-0)/16 = 0

12 is positive because it is has the same direction as I
V is negative because it opposes I.

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