Superposition Theorem On AC Analysis

   
       The superposition theorem in ac circuit is just the same on dc circuits. What is add on ac is just there's a presence of Impedance which are the conductor and capacitor. They had a variable and value. But the process is just the same, which all sources (except dependent sources) other than the one being considered are eliminated and then replace current sources with opens, replace voltage sources with shorts. Based on the book, The superposition theorem can be stated as follows:

        The current in any given branch of a multiple-source circuit can be found by determining the currents in that particular branch produced by each source acting alone, with all other sources replaced by their internal impedances. The total current in the given branch is the phasor sum of the individual source currents in that branch.

The procedure for the application of the superposition theorem is as follows:

Step 1. Leave one of the sources in the circuit, and replace all others with their internal impedance. For ideal voltage sources, the internal impedance is zero. For ideal current sources, the intemal impedance is infinite. We will call this procedure zeroing the source.

Step 2. Find the cunent in the branch of interest produced by the one remaining source.

Step 3. Repeat Steps 1 and 2 for each source in turn. When complete, you will have a number of current values equal to the number of sources in the circuit.

Step 4. Add the individual current values as phasor quantities.


Here are an example of Superpostion Theorem, but these videos are just in dc circuit, as like what I've said earlier in ac circuit there's a presence of impedances and solving these are just the same in dc analysis.

Insight Learning:

To calculate the contribution of each source independently, all the other sources must be removed and replaced without affecting the final result.

When removing a voltage source, its voltage must be set to zero, which is equivalent to replacing the voltage source with a short circuit.

When removing a current source, its current must be set to zero, which is equivalent to replacing the current source with an open circuit.