What is the Mesh Current Analysis for Finding i0 in a Circuit?

AI Thread Summary
Mesh current analysis is used to find the current i0 in a circuit with a 3A current source. The analysis involves creating equations based on Kirchhoff's Voltage Law (KVL) and identifying a supermesh due to the current source. The initial equations derived for the mesh currents i1, i2, and i3 contained an algebraic error, which was corrected to yield the correct relationship between the currents. After resolving the equations, the calculated value for i0 was found to be close to the expected result, highlighting the importance of accuracy in circuit analysis. Small algebra mistakes can significantly impact the final outcomes in circuit calculations.
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Homework Statement


Find i0 in http://images3a.snapfish.com/232323232%7Ffp73395%3Enu%3D52%3A%3A%3E379%3E256%3EWSNRCG%3D3359%3B24399347nu0mrj" using mesh current analysis.

Note that the ^i1, ^i2 and ^i3 are to label my currents and show they are flowing clockwise. i0--> is the direction of the i0 current. The current source is 3A.

Homework Equations



KVL
KCL
Ohm's law

The Attempt at a Solution



So i know that the current sources makes a supermesh and that you basically remove it from the circuit and do mesh analysis 'around the path of the supermesh' and you will get a constraint equation from the supermesh for your 3rd equation.

So for i1 I got:

2i_{1} + 6 + 4(i_{1}-i_{3})+ (i_{1}-i_{2}) = 0

2i_{1} + 4i_{1} - 4i_{3} + i_{1} - i_{2} = -6

8i_{1} - i_{2}-4i_{3}=-6

So the supermesh i got:

5i_{2} + (i_{2}-i_{1}) + 4(i_{3}-i_{1})+12=0

5i_{2} + i_{2} - i_{1} + 4i_{3}-4i_{1}=-12

-5i_{1} + 6i_{2} + 4i_{3} = -12

and the constraint equation:

i_{3}=i_{2}+3

0i_{1}-i_{2}+i_{3} = 3

which makes a 3x4 matrix now i got:

i_{1}=-1.09a

i_{2}=-2.945a

i_{3}=.054a

and i believe that i0 in the circuit should be i2-i1 but they are looking for -1.73a for i0 which is close to but not what you get with my numbers so where did I go wrong?

thanks!
 
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[PLAIN]https://www.physicsforums.com/latex_images/31/3122511-1.png

In eq1, I think it should be 7 I1 shouldn't it? You have 8 I1
 
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bah I hate when that happens, now it works out! Those small algebra mistakes really bite you in circuit analysis huh? lol

Thanks though vk6kro
 
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