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

In summary, the conversation discusses using mesh current analysis to find the value of i0 in a circuit with a current source. The equations used include KVL, KCL, and Ohm's law. The attempt at a solution involves finding the values of i1, i2, and i3 using a 3x4 matrix. A small algebraic mistake is identified and corrected, resulting in the correct value for i0.
  • #1
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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:

[tex] 2i_{1} + 6 + 4(i_{1}-i_{3})+ (i_{1}-i_{2}) = 0 [/tex]

[tex] 2i_{1} + 4i_{1} - 4i_{3} + i_{1} - i_{2} = -6 [/tex]

[tex] 8i_{1} - i_{2}-4i_{3}=-6 [/tex]

So the supermesh i got:

[tex] 5i_{2} + (i_{2}-i_{1}) + 4(i_{3}-i_{1})+12=0[/tex]

[tex] 5i_{2} + i_{2} - i_{1} + 4i_{3}-4i_{1}=-12 [/tex]

[tex] -5i_{1} + 6i_{2} + 4i_{3} = -12 [/tex]

and the constraint equation:

[tex] i_{3}=i_{2}+3 [/tex]

[tex] 0i_{1}-i_{2}+i_{3} = 3 [/tex]

which makes a 3x4 matrix now i got:

[tex] i_{1}=-1.09a [/tex]

[tex] i_{2}=-2.945a [/tex]

[tex] i_{3}=.054a [/tex]

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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  • #2
[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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  • #3
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
 

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

1. What is mesh current analysis?

Mesh current analysis is a method used in circuit analysis to determine the current flowing through each individual loop or mesh in a circuit. It is based on Kirchhoff's Voltage Law and Ohm's Law.

2. When should I use mesh current analysis?

Mesh current analysis is typically used when there are multiple current sources in a circuit and the goal is to find the current flowing through each individual loop. It is also helpful when analyzing circuits with parallel branches.

3. What are the steps for performing mesh current analysis?

The steps for performing mesh current analysis are:
1. Identify and label each mesh in the circuit
2. Apply Kirchhoff's Voltage Law to each mesh, setting the sum of the voltage drops equal to 0
3. Write equations for each mesh using Ohm's Law (V=IR) for each resistor
4. Solve the resulting system of equations to find the current flowing through each mesh

4. What are the advantages of using mesh current analysis?

Mesh current analysis allows for a systematic and organized approach to solving complex circuits with multiple current sources. It also eliminates the need for simultaneous equations, making it easier to solve for the unknown currents.

5. Are there any limitations of mesh current analysis?

Mesh current analysis is only applicable to circuits with multiple current sources and cannot be used for circuits with only one current source. It also assumes an ideal circuit with no mutual inductance or capacitance between loops. In some cases, it may not provide the most accurate results and other methods of circuit analysis may be more suitable.

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