# Homework Help: Solve by superposition method

1. Jul 12, 2009

### noppawit

I'm solving by using superposition, I would like to ask that my solution is correct or not.

By the way, the question is "Find v0"

Last edited by a moderator: May 4, 2017
2. Jul 12, 2009

### cepheid

Staff Emeritus
I don't know about superposition, but if you use KCL at the top node, you have three branches:

The left branch has the current source and two resistors.

The right branch has the voltage source and two resistors.

The middle branch has the remaining resistor.

KCL says that:

current going into node = current coming out of node

which, in this case means:

current in left branch + current in right branch = current in middle branch.

I called the current in the right branch i0, which makes v0 = i0R. I get a significantly different answer (-1.00 V), which I confirmed using a circuit-solving program.

3. Jul 16, 2009

### CEL

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You made two mistakes in the second equation. Since $$i_x$$ is entering the plus sign of the voltage source, it should enter the equation as +9V, instead of -9V.
Also, $$R + R + \frac{2}{3}R = \frac{8}{3}R$$, not $$\frac{32}{3}R$$

Last edited by a moderator: May 4, 2017
4. Jul 16, 2009

### Redbelly98

Staff Emeritus
IIRC, when treating the 9V source you would replace the current source with an open circuit, not a short. So the 2/3 R was incorrect to begin with.

5. Jul 16, 2009

### CEL

You are right.