# KIRCHOFF's Law: Solving Circuit

• urduworld
In summary, the conversation discusses the calculation of current in two loops in a circuit, where one loop has a clockwise direction and the other has a counterclockwise direction. The magnitude of the current is positive for both loops, and the direction of the current can be defined by the user as long as it is consistent. The conversation also briefly mentions a separate question about complex DC circuits.
urduworld

according to circuit
In Left Loop Current is I1 and Right Loop is I2

Now Loop Left
10-8I1-3I1-I2=0
which becomes
10-8I1-3I1+3I2=0
11I1-3I2-10=0 ------------eq 1

Now Loop Right
15-6I2-3I2-I1=0
15-6I2-3I2+3I1=0
3I1-9I2+15=0
I1-3I2+5=0 ---------------eq 2

Deduct eq 2 from eq 1

10I1-15=0
I1= 1.5
from eq 2 we have
I2=2.1666

I= I1-I2
or
I=I2-I1
or what and how to take decision what i have to do

When you consider the magnitude of the current it should be +ve. So I = I2 - I1

Thanks Bhat i got your point, and one thing more what will be the direction current on both the loop

Since you defined I1 and I2 to be clockwise for positive currents, and both currents are in fact positive, then the direction of each is _____?

yes direction of current is positive in the diagram what if direction is counter-clock wise and one loop clock wise and othe one counter clock wise

It doesn't matter how you define things, as long as you are consistent. When you assume one loop to be CW and the other CCW, current on the R3 will be sum of the currents in both loops. If you have assumed wrong (that is, currents don't go as you expect them) one of the currents in your final solution will be negative - and that's perfectly OK, that just means current flows in the opposite direction.

Thanks Borek now i 'm clear about Kirchoff

what is a comlex dc circuit

haroon1972 said:
what is a comlex dc circuit

Hello harroon1972, welcome to PF!

If you have a separate question unrelated to what the OP (original poster) was asking, you should start a new thread for it. I'd be happy to help, but you need to be more specific. As it stands right now, it's not very clear what you're asking.

## 1. What is Kirchhoff's Law and why is it important in circuit analysis?

Kirchhoff's Law, also known as Kirchhoff's Circuit Laws, are two fundamental laws in circuit analysis that govern the behavior of electrical circuits. These laws help determine the current and voltage in different parts of a circuit, making it an essential tool for analyzing and designing circuits.

## 2. What are the two laws in Kirchhoff's Law and how are they applied in circuit analysis?

The two laws in Kirchhoff's Law are the Kirchhoff's Current Law (KCL) and Kirchhoff's Voltage Law (KVL). KCL states that the total current entering a node is equal to the total current leaving the node, while KVL states that the sum of all voltages in a closed loop is equal to zero. These laws are applied in circuit analysis by creating equations that represent the flow of current and voltage in a circuit.

## 3. How do you solve a circuit using Kirchhoff's Law?

To solve a circuit using Kirchhoff's Law, you must first identify all the nodes and loops in the circuit. Then, apply KCL at each node and KVL in each closed loop to create a system of equations. Finally, solve the equations to determine the currents and voltages in the circuit.

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

Yes, Kirchhoff's Law can be applied to any type of circuit, including series, parallel, and complex circuits. It is a universal law that applies to all electrical circuits.

## 5. What are the limitations of Kirchhoff's Law in circuit analysis?

Kirchhoff's Law assumes that the components in a circuit are linear and that the circuit is in a steady-state. This means that it may not accurately predict the behavior of non-linear or time-varying circuits. Additionally, it does not take into account the effects of capacitance and inductance, which may affect the accuracy of the analysis in high-frequency circuits.

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