# In serious need of a/c circuits help

• Engineering
In summary, the conversation discusses solving a circuit problem using Kirchoff's laws and MATLAB. The problem involves using KCL and KVL to set up a matrix and solving for currents. The solution is then checked using the nodal method. The next step is to solve for the voltage using the current and the nodal method.

## Homework Statement

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

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.

Last edited by a moderator:
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

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

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!

## 1. What are the basic components of an A/C circuit?

The basic components of an A/C circuit are a power source (such as a battery or generator), wires to carry the current, and a load (such as a light bulb or motor).

## 2. How does an A/C circuit differ from a D/C circuit?

An A/C (alternating current) circuit uses a power source that alternates the direction of the current flow, while a D/C (direct current) circuit uses a power source that maintains a constant direction of current flow.

## 3. What is the purpose of a capacitor in an A/C circuit?

A capacitor is used to store electrical charge and can help regulate the flow of alternating current in a circuit. It can also be used to block certain frequencies of current.

## 4. How do I calculate the total impedance in an A/C circuit?

To calculate the total impedance in an A/C circuit, you can use the formula Z = √(R^2 + (Xl - Xc)^2), where R is the resistance, Xl is the inductive reactance, and Xc is the capacitive reactance.

## 5. How can I troubleshoot problems in an A/C circuit?

If you are experiencing issues with an A/C circuit, you can troubleshoot by checking all connections, inspecting for any damaged components, and using a multimeter to measure voltage, current, and resistance at different points in the circuit.

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