# Homework Help: Superposition Problem

1. Jun 20, 2007

### another813

Apply Superposition to the circuit of Fig (5) to find i3.

i3 is above the 100v source flowing upward.

I have provided the problem on the attachment.

Like the theorem states, I have the 3 different re-drawings with the sources short circuited and removed. I have been surfing for hours trying to find a similar problem to help me out.

I do understand how to do like it is on this website http://www.wisc-online.com/objects/index_tj.asp?objID=DCE3802 .

I am just confused on what I should do next on my problem. I am not expecting someone to just give me the answer rather to just give me a hint on what I need to next.

-Daniel
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

#### Attached Files:

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2. Jun 21, 2007

### ranger

Hi Daniel (welcome to PF, btw),

Your redraws look good. But consider redrawing even more. If you take redraw number 1 where you only consider the current source, what would the equivalent circuit look like? Remember that the V1 has been replaced by its ideal internal resistance, therefore we have a short in parallel with U4 and R4. When we have such a situation what happens?

If you simplify your redraws more, you'll be able to find I3 due to each one of these sources, the finally you'll add or subtract them depending on current direction to get the resultant.