# Kirchhoff's Laws and Circuit Equation Help Request

• sozener1
In summary, the potential differences around the loops of wire are equal, and the result is that i3+i4 is equal to i5.
sozener1
how do i calculate potential differences around the loops

is i3+i4 equal to i5??

this is actually from maths and i completely forgot how to do calculation around electrical circuits from physics

#### Attachments

• aefa.PNG
31.4 KB · Views: 470
hi sozener1!
sozener1 said:
is i3+i4 equal to i5??

hint: the eg top-right-hand corner is also a node, and has one current going in and one current going out

sooo … ?

Note: Thread title changed to make it more descriptive of the thread content.

Hi,
actually you need only one more equation, since i1=i2, i3=i4 and i6 and i5 can be omited because they make no potential difference since they flow through short circuit.
So the last equation is 0=i3 x R + i3 x R - i7 x R

Hey there! It looks like this problem is just a use of mesh analysis without explicitly stating it.

So, if you look at the loop of wire that has the voltage source connected to it in series, you know that the current in that loop of wire must be constant. This is a fundamental principle of current.

What can you get from this? Well, it looks like i1 = i2 = i6

Not only this, but on the strand of wire on the right, this same principle can be applied.

If you use Kirchoff's voltage law around the first loop of wire on the left, you can see that:

(Going in defined direction of current) = V+i1R+i7R = 0, also, I think they made a mistake or misused the notation, because the shorter side of a voltage source is supposed to be the negative end.

From there, notice that i7 would have to be the net current between i1 and i3, and use the voltage rule around your second strand of wire in order to form another equation. After that, it is purely substitution, and assuming those R values are all equal, you'll have a nice result.

## 1. What are Kirchhoff's Laws?

Kirchhoff's Laws are two fundamental laws in circuit analysis, named after German physicist Gustav Kirchhoff. The first law, also known as Kirchhoff's Current Law (KCL), states that the sum of currents entering a node or junction in a circuit must equal the sum of currents leaving that node. The second law, known as Kirchhoff's Voltage Law (KVL), states that the sum of voltage drops around a closed loop in a circuit must equal the sum of voltage gains.

## 2. How do Kirchhoff's Laws help in solving circuit equations?

Kirchhoff's Laws provide a systematic approach to analyzing complex circuits and solving circuit equations. By applying KCL and KVL to different parts of a circuit, we can determine the values of currents and voltages at various points in the circuit. This allows us to find unknown values and predict the behavior of the circuit.

## 3. What is the difference between Kirchhoff's Current Law and Kirchhoff's Voltage Law?

As mentioned earlier, KCL deals with the sum of currents at a node, while KVL deals with the sum of voltage drops around a closed loop. Another key difference is that KCL is based on the principle of conservation of charge, while KVL is based on the principle of conservation of energy. In simpler terms, KCL looks at the flow of charge, while KVL looks at the flow of energy.

## 4. Can Kirchhoff's Laws be applied to all types of circuits?

Yes, Kirchhoff's Laws can be applied to all types of circuits, as long as they are made up of passive elements such as resistors, capacitors, and inductors. These laws can also be extended to more complex circuits by using equivalent circuits and simplifying the analysis.

## 5. Are there any limitations to Kirchhoff's Laws?

Kirchhoff's Laws have certain limitations, such as assuming ideal conditions in a circuit. This means that the laws may not accurately predict the behavior of circuits with non-ideal components, such as those with non-linear elements. Additionally, the laws may be difficult to apply in circuits with multiple sources and multiple loops. However, with some modifications and techniques, Kirchhoff's Laws can still be used to solve these types of circuits.

• Introductory Physics Homework Help
Replies
9
Views
2K
• Introductory Physics Homework Help
Replies
10
Views
1K
• Introductory Physics Homework Help
Replies
16
Views
1K
• Introductory Physics Homework Help
Replies
7
Views
647
• Introductory Physics Homework Help
Replies
4
Views
3K
• Introductory Physics Homework Help
Replies
5
Views
518
• Introductory Physics Homework Help
Replies
5
Views
926
• Introductory Physics Homework Help
Replies
2
Views
1K
• Introductory Physics Homework Help
Replies
5
Views
1K
• Introductory Physics Homework Help
Replies
6
Views
2K