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posted by  shorty09 on 4/22/2008 10:30:21 AM  |  status: Live  

Circuit Analysis

Course Textbook Chapter Problem
Algebra Based Physics N/A N/A N/A
Question Details:

 
What is the current through R2? please give an numerical answer, not just equations for full points.
 
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posted by Anonymous on 4/22/2008 10:50:16 AM  |  status: Live
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shorty09's comment:
"thanks!!1"
Response Details:
Use loop analysis.
 
6=4I2+1(I1-I2)
4=2I2+1(I2-I1)
 
Gives both I1 & I2. Solving is easiest through matrix equations or simutanious equations.
If you have a graphing calculator, it will do it for you, and you can copy it down.
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posted by Michaelh on 4/22/2008 10:55:01 AM  |  status: Live
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shorty09's comment:
"thanks!!!"
Response Details:
Use loop analysis:
 
Let the current in the left circuit be I1.
Let the current in the right circuit be I2.
 
We will also make the assumption that all currents are clockwise
 
For the loop on the left:
 
-4 + 2I1 + (I1 - I2) =0            =>            3I1 - I2 = 4 ......... (1)
 
For the loop on the right:
 
1(I2 - I1) + 6 + 4I2 =   0            =>         -1I1 + 5I2 = -6 ....... (2)
 
 
Solving (1) and (2)
 
I1 = 1A
I2 = -1A
 
So, the current in R2 is I1 - I2 = 1 - (-1) = 2A
Michael
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