# Homework Help: Very very very short question circuit analysis please?

1. Apr 12, 2013

### Questions999

I am solving a VERY complicated exercise and I have this part that I dont understand.The image posted is a very big simplification of a part of the exercise.I have to find the potential between A and B.My question : Are the 15 Volt and the 13 Volt in the picture involved in the calculation?
I know I have to calculate the potential using Kirch.law btw.

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2. Apr 12, 2013

### Staff: Mentor

Do the lines represent wires only? If so, the 13V and 15V sources have no effect on the KVL sum from A to B.

3. Apr 12, 2013

### Questions999

The lines represent wires and they have resistances in it.

4. Apr 12, 2013

### CWatters

Not if one end is open circuit. Are they really open circuit?

5. Apr 12, 2013

### Staff: Mentor

That's a confusing statement. Are the lines wires, with the resistances represented by the circled potential changes? Or are there hidden potential changes in the lines along the path from A to B?

6. Apr 12, 2013

### Questions999

Sorry.13 V is also resistance,15 V is only wire.

7. Apr 12, 2013

### Staff: Mentor

How can a wire be 15 V? Do you mean it is a wire that is at a 15 V potential, or leads to a 15 V source? Something like this:

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8. Apr 12, 2013

### Questions999

Wire that has a 15 V potential.The image is very right!

9. Apr 12, 2013

### Staff: Mentor

Okay. Then consider that a single node can only be at a single potential; there is no potential difference between any points connected by a contiguous wire. In this case, the blue wires in the figure represent one node. The only potential changes that occur along the path from A to B are those due to the 12 V and 14 V drops.