Thevenins Theorem on AC Analysis

           Solving on Thevenins theorem in ac anaylsis, is just the same process in dc analysis, which we've  done to tackle. The difference is in ac, there's a presence of impedance which involve in solving series-parallel combination.

Thevenins Theorem states that:

            Any combination of sinusoidal AC sources and impedances with two terminals can be replaced by a single voltage source  e and a single series impedance z. The value of e is the open circuit voltage at the terminals, and the value of z is e divided by the current with the terminals short circuited. In this case, that impedance evaluation involves a series-parallel combination.

Summary of Thevenin's Theorem

    Remember that the Thevenin equivalent circuit is always a voltage source in series with a resistance regardless of the original circuit that it replaces. The significance of Thevenin's theorem is that the equivalent circuit can replace the original circuit as far as any external load is concerned. Any load connected between the terminals of a Thevenin equivalent circuit experiences the same current and voltage as if it were connected to the terminals of the original circuit.

A summary of steps for applying Thevenin's theorem follows.


Step 1. Open the two terminals between which you want to find the Thevenin circuit, This is done by removing the component from which the circuit is to be viewed.


Step 2. Determine the voltage across the two open terminals.

Step 3. Determine the impedance viewed from the two open terminals with ideal voltage sources replaced with shorts and ideal current sources replaced with opens (zeroed).

Step 4. Connect Vr7, andZ,Tinseies to produce the complete Thevenin equivalent circuit.

Here are some example of solving thevenins theorem(note that they are the same process on solving the thevenins theorem through ac analysis in a dc analysis):

Insight Learnings:

       Remember that the Thevenin equivalent circuit is always a voltage source in series with a resistance regardless of the original circuit that it replaces. The significance of Thevenin's theorem is that the equivalent circuit can replace the original circuit as far as any external load is concerned. Any load connected between the terminals of a Thevenin equivalent circuit experiences the same current and voltage as if it were connected to the terminals of the original circuit.