Kirchhoff's Rules Homework Solution

In summary, the conversation discusses finding Kirchoff's laws for a given circuit, specifically the loop rule and junction rule. The participant provides equations and mentions using a matrix to solve them, but notes that the resulting currents are all zero which doesn't make sense. It is suggested to label the diagram and ensure that all necessary equations are included.
  • #1
ma18
93
1

Homework Statement



Find Kirchoff's laws for this
http://postimg.org/image/d78dvdg5f/

(Actual problem has a bit more but I can do that part.)

Homework Equations



Loop rule
Junction rule

The Attempt at a Solution



I got the following equations

2e - 4i_4 - 2i_2 = 0
e - 3i_3 - i_1 = 0
e - 4i_4 - i_1 = 0
2e - 3i_3 - 2i_2 = 0
3e - i_1 - 2i_2 = 0

I used these in a matrix but when I reduced to rref I got zero's for the currents which doesn't make sense.

Thanks,

P.S This is from a 2nd year Uni course
 
Last edited:
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  • #2
It helps to label your diagram.
You appear to have put ##e=\varepsilon/R##
I don't see where 3e comes from.

You have three loops - but 5 loop equations - this means that you will get zero lines in the matrix (some of rows are linear combinations of the others) and you appear to have no junction-rule equations: these will not have any e's in them. So your system of equations may be incomplete.
 

1. What are Kirchhoff's Rules?

Kirchhoff's Rules, also known as Kirchhoff's Laws, are fundamental principles in circuit analysis that describe the behavior of electrical circuits. They were developed by German physicist Gustav Kirchhoff in the mid-19th century and are used to determine the current and voltage in various parts of a circuit.

2. What are Kirchhoff's Current Law (KCL) and Kirchhoff's Voltage Law (KVL)?

Kirchhoff's Current Law states that the total current entering a junction in a circuit must be equal to the total current leaving that junction. This is based on the principle of conservation of charge. Kirchhoff's Voltage Law states that the sum of all voltage drops in a closed loop in a circuit must be equal to the sum of all voltage rises. This is based on the principle of conservation of energy.

3. How do Kirchhoff's Rules help in solving circuit problems?

Kirchhoff's Rules provide a systematic method for analyzing complex circuits and determining the values of currents and voltages. By applying KCL and KVL to different parts of a circuit, we can create a set of equations that can be solved to find the unknown values. This allows us to predict the behavior of a circuit and troubleshoot any issues.

4. Can Kirchhoff's Rules be applied to any type of circuit?

Yes, Kirchhoff's Rules can be applied to any type of circuit, whether it is a simple series or parallel circuit or a more complex network of interconnected components. They are based on fundamental principles of physics and can be used to analyze circuits with resistors, capacitors, and inductors.

5. Are there any limitations to Kirchhoff's Rules?

Kirchhoff's Rules are based on idealized assumptions and may not hold true in all situations. For example, they assume that all components in the circuit are connected by ideal wires with no resistance, which is not always the case in real-life circuits. Additionally, they do not account for non-linear components such as diodes and transistors. However, in most practical applications, these limitations can be ignored and Kirchhoff's Rules provide accurate results.

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