Advanced Techniques for Circuit Analysis-電路學筆記

一定愛配陳晏笙教授的開放課程食用: 課程連結

Advanced Techniques for Circuit Analysis

Nodal Analysis(Node-Voltage Method)

The Idea of Nodal Analysis

• The prvious method: Using "branch current" as the variable.
• Nodal method: Using node voltage as the variable.
  • Each branch voltage can be obtained from nodal voltages.
  • The corresponding branch current can be obtained through its component model.

The Steps of Doing Nodal Analysis

1. Finding nodes, setting variables.
2. Setting reference node.
3. Do KCL analysis with component models.
4. With "dependent voltage source", get the equation by setting "SuperNode".
5. With "dependent current source", replace the variable with the variable you set.
6. Done!

Examples

Mesh Analysis(Mesh-Current Method)

The Idea of Mesh Analysis

• The prvious method: Using "branch voltages" as the variable.
• Nodal method: Using "mesh currents" as the variable.
  • Each branch current can be obtained from mesh currents.
  • The corresponding branch voltage can be obtained through its component model.

The Steps of Doing Mesh Analysis

1. Finding meshes, setting variables.
2. Do KVL analysis with the variable you set.
3. With "dependent voltage source, replace the variable with the variable you set.
4. With "dependent current source",
   
5. Done!

Examples

Nodal Analysis vs Mesh Analysis

• Which one do we prefer to use?
  • It depends on......
  

Superstition Theorem

Linear Systems

• A circuit can be considered as a linear system.

  

• Properties of linear system

  • Homogeneous property

    • If , then

    • Ex:

      

  • Additive property

    • If , f(x_2)=y_2$, then

    • Ex:

      

How to use superstition theorem?

1. Divide the circuit into types according to how many independent electric sources it gets.
2. For "independent voltage source" => make the part of the circuit short, then evaluate the current/voltage value.
3. For independent current source => break the part of the circuit, then evaluate the desired current/voltage value.
4. With the properties of linearity, sum all voltage/current value together, the result is the final voltage/current value.

Examples of Superstition Theorem

Source Transformation(可略)

• Basic Concept

  

• Case 1

  • 

• Case 2

  • 

Thevenin and Norton Equivalents

Thevenin Equivalents

• The objective of Thevenin Equivalent Circuit

  • To simplify the process of evaluating the value of a specific part of a circuit.

• What exactly is Thevenin Theorem doing?

  • A linear two-terminal circuit can be replaced by an equivalent circuit consisting of a voltage source in series with a resistor

  

  • and

    • => the open-circuit voltage at the terminals.

      

    • => The input resistance at the terminals when the "independent" source are turned off. The value can also be known by applying a "testing current/voltage source" as a load of a circuit.

      

      

      

• Examples

單元 12 ．進階電路分析 - 戴維寧等效電路與諾頓等效電路(51:17)