Tuesday 7 July 2015

Kirchhoff Current Law | Easy to understand KCL with examples and solutions

Kirchhoff Current states that the sum of all currents at any node is equal to zero.
OR
The sum of all currents entering any point is equal to sum of all currents leaving that point.
Kirchhoff Current law is fundamental law of Electric Circuits which explains an equal relationship between amount of Current that enters and exits through any specific point.
Now let’s take an example of understanding the concept of Kirchhoff current law.
Image displaying example of Kirchhoff Current law

Consider the point marked with circle in the figure, the point is acting as ‘node’. Remember that ‘node’ is the point, where two or more than two wires meet.

Now we will apply KCL to node. The total amount of current entering on the node is 10 A, According to KCL the ‘Current IN’ in present case is 10 A. While the current leaving the node is 5+5 Amp which makes 10 A in total.

Mathematically if we apply KCL on that point, then
∑ Current IN = ∑ Current Out 
10 A = 5 A + 5 A
10 A= 10 A
Which verifies KCL
Now lets take another example understand KCL in easy way.

In diagram there are 6 value of Current. I 1, I 2, I 3 , I 4, I 5 and I 6. In case we have to find two values I 5 and I 6. Two nodes shown with red and yellow color are present. Red node has one unknown current I 5 flowing away from the node, where yellow node has two unknown currents I 5 and I 6.

While solving problem, remember to start from Node which has lowest number of unknown values. Now, on red node, first calculate total amount of currents flowing to point. In this I 1 = 20 A is flowing towards the point. Whereas I 2, I 3, I 4 and I 5 are flowing away from the node.

Apply mathematical equation.
∑Current IN= ∑Current Out
I 1 = I 2 + I 3 + I 4 + I 5
20 A = 15 A + 3 A + 1 A + I 5
20 A – 15 A – 3 A – 1 A = I 5
1 A = I 5
So value of I 5 is 1 A
To find value of current on point I 6 again apply KCL on yellow node.
∑Current IN= ∑Current Out
I 4 + I 5 = I 6
1 A + 1 A = I 6
2 A = I 6
or I 6 = 2 A

Friday 22 May 2015

Ohm Law | Experimental verification of Ohm law

Ohm law describes relationship between voltage and current applied across any conductor. Ohm law states: The current flowing through a conductor is directly proportional to Voltage (potential difference), keeping the Resistance constant.
Mathematically

Wednesday 20 May 2015

Electric Circuit Fundamentals | Basics of Electrical Engineering

Electric Circuit Fundamentals is basic course of Electrical Engineering. It contains Kirchoff laws, Ohm law, Voltage Divider, Current Divider and other basic concepts studied at High School.
Ohm Kirchoff Voltage Divider and other laws mentioned
  1. Ohm Law
  2. Kirchoff Current Law