# problem 2 on superposition

Discussion in 'Homework Help' started by electronicstech07, Nov 2, 2008.

1. ### electronicstech07 Thread Starter Member

Nov 16, 2007
18
0
I have attached my work on another problem involving superposition. It involves a Is and Vs and is asking me to find Ir3. Help is much appreciated!

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2. ### vvkannan Active Member

Aug 9, 2008
138
11
While calculating I (killing Vs) entering at B the resistance in the denominator should be the sum of total resistance.I think you have made a mistake there.

3. ### electronicstech07 Thread Starter Member

Nov 16, 2007
18
0
You're correct again. I guess I'm going a little too fast calculating the answer on some of these problems. Thanks again!

4. ### hgmjr Moderator

Jan 28, 2005
9,030
218
What is the answer given in the book?

hgmjr

5. ### electronicstech07 Thread Starter Member

Nov 16, 2007
18
0
The answer is 1.6 mA and that is what I got when correcting the value of the denominator to 852.5 ohms when calculating for I entering pt. B.

I entering pt. B = 680/852.5 * 100 mA = 79.76 mA.

Using I divider, Ir3 = 220/1020 ohms * 79.76 mA = 17.2 mA

Solving for Ir3, 17.2-15.6 = 1.60 mA.

6. ### hgmjr Moderator

Jan 28, 2005
9,030
218
Here is the Millman's Theorem approach to the problem.