In serious need of a/c circuits help

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Discussion Overview

The discussion revolves around solving AC circuit problems using Kirchhoff's laws and MATLAB. Participants are addressing specific homework questions related to circuit analysis, including the use of KCL (Kirchhoff's Current Law) and KVL (Kirchhoff's Voltage Law) to set up equations and matrices for solving currents and voltages in the circuit.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant describes their approach to solving a circuit problem using KCL and KVL, setting up a matrix in MATLAB to find the currents at each corner.
  • Another participant suggests that the original poster should show more of their attempt and consider posting in the engineering forum.
  • A participant shares their calculations using KVL and KCL, detailing the equations they derived for the circuit and the resulting matrix from MATLAB.
  • There is mention of uncertainty regarding the correctness of the calculated voltage Vo, with one participant expressing doubt about their result.
  • Another participant confirms the calculated value of Vo and suggests that it can also be solved using the nodal method, indicating they arrived at the same result.

Areas of Agreement / Disagreement

There is some agreement on the approach to solving the circuit problems, particularly regarding the use of KCL and KVL. However, uncertainty remains about the correctness of specific calculations, and not all participants are familiar with mesh analysis, indicating a lack of consensus on the methods used.

Contextual Notes

Participants express varying levels of familiarity with circuit analysis techniques, and there are references to specific methods (mesh analysis, nodal method) that some participants may not fully understand. The discussion includes assumptions about the application of Kirchhoff's laws and the use of MATLAB for calculations.

Who May Find This Useful

Students studying electrical engineering or related fields who are working on circuit analysis problems, particularly those involving AC circuits and the application of Kirchhoff's laws.

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Homework Statement


[PLAIN]http://img233.imageshack.us/img233/5697/img1251b.jpg


Homework Equations


KCL, KVL?


The Attempt at a Solution


For problem two I was able to use kcl and kvl to set up a matrix to solve for the 4 currents (at each corner) but i need to plug it into MATLAB as soon as i figure out how. Aside from that I am completely lost.
 
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should probably show some attempt, and put this in the engineering forum
 
Tom McCurdy said:
should probably show some attempt, and put this in the engineering forum

Ok i took what i had so far for number to and used MATLAB to try and figure out Vo

What i did was use kvl of the top two loops together to get
0=-j4(I1)+6(I2)+j5(I2-I4)+8(I1-I3)

then kcl at the top right mesh to get
I1-I2=-4

KVL @ bottom left to get
0=-10+8(I3-I1)+(-j2)(I3-I4)

And
I4=-3

Set up a matrix and used MATLAB to get it in rref which gave

Code: 
   1(I1)            0                  0                  0            -1.8690 - 4.4276i
   0                 1(I2)             0                  0             2.1310 - 4.4276i
   0                 0                  1(I3)             0             0.2828 - 3.6069i
   0                 0                  0                  1(I4)       -3.0000

then (not really sure about this part)
used Io (current going up from borrom center through Vo)=I4-I3
used MATLAB and did I4-I3 which gave me Io=3.2828 - 3.6069i

then Vo=Io(-j2) ??
That gives me -7.2138 - 6.5655i but I am not sure if that's correct of not.
 
For question 1 you need to label the nodes and calculate the voltage differences and currents, by using Kirchoff's laws.
I don't know how to do question 2, because my single EE course didn't cover mesh analysis
The last question is done by solving the circuit with only one source turned one and doing that for each source, adding the final answers if I recall correctly
 
shadow7874 said:
then Vo=Io(-j2) ??
That gives me -7.2138 - 6.5655i but I am not sure if that's correct of not.

This is correct. It can also be solved by the nodal method, and doing so, I get the same result.

Now you only have two more to do!
 

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