Sup erposition
We use Nodal Analysis and Mesh Analysis to determine the specific variable (voltage or current) if the circuit has two or more independent sources. Aside from Nodal and Mesh Analysis, Superposition is another way to determine the contribution of each independent source to the variable and then add them up.
The superposition principle states that the voltage across (or current through) an element in a linear circuit is the algebraic sum of the voltage across (or current through) that element due to each independent source acting alone.
In order to use Superposition Principle, always keep these two things in mind:
1. Consider one independent source at a time while the other independent sources are turned off. Replace every voltage source by 0V and replace every current source by 0A (open circuit).
2. Dependent sources are left intact because they are controlled by circuit variables.
Steps to Apply Superposition Principle:
1. Turn off all independent sources except one source (Either independent voltage or current source). Find the output (voltage or current) due to that acting source using Nodal or Mesh Analysis or KCL or KVL.
2. Repeat step 1 for each of the other independent sources.
3. Find the total contribution by adding algebraically all the contributions.
Other terms such as killed, made inactive, deadened, or set equal to zero are often used to convey the same idea.
(We are comfortable using the word killed. Most of our examples, you will see that we are using the word killed but don't be frightened we are not killing people just killing independent voltages and currents only.)
The superposition principle states that the voltage across (or current through) an element in a linear circuit is the algebraic sum of the voltage across (or current through) that element due to each independent source acting alone.
In order to use Superposition Principle, always keep these two things in mind:
1. Consider one independent source at a time while the other independent sources are turned off. Replace every voltage source by 0V and replace every current source by 0A (open circuit).
2. Dependent sources are left intact because they are controlled by circuit variables.
Steps to Apply Superposition Principle:
1. Turn off all independent sources except one source (Either independent voltage or current source). Find the output (voltage or current) due to that acting source using Nodal or Mesh Analysis or KCL or KVL.
2. Repeat step 1 for each of the other independent sources.
3. Find the total contribution by adding algebraically all the contributions.
Other terms such as killed, made inactive, deadened, or set equal to zero are often used to convey the same idea.
(We are comfortable using the word killed. Most of our examples, you will see that we are using the word killed but don't be frightened we are not killing people just killing independent voltages and currents only.)