Download Lecture Notes Chapter 3

Introduction to Electrical & Computer Engineering
Node Voltage Analysis
• Lee Brinton
• Salt Lake Community College
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Introduction to Electrical Engineering
Node Voltages
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Comparison between Elevation and Voltage
Branch Voltages Vs. Node Voltages
Nodes and Extraordinary (Critical) Nodes
Node Analysis Process
Node Analysis with Dependent Sources
Supernodes
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Similarities Between Elevation and Voltage
Mount Olympus
Salt Lake Valley Floor
Sea Level
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Branch and Node Voltages
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Branch Currents and Voltages
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Nodes and Extraordinary (Critical) Nodes
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Node Voltage Process
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Steps to Performing Node Analysis
1. Identify extraordinary (critical) nodes
2. Select one node as the reference node (V = 0)
3. Assign variable names to the other extraordinary nodes
4. Write node equations at each other node in terms of the
node voltage variables
5. Solve the system of equations for the node voltages
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Example Circuit
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Example Circuit
+ V10 -
𝑖15 =
𝑉2
15
= 1.38 A
𝑉10 = 𝑉2 − 𝑉1 = −6.21 𝑉
V1 = 14.48
V2 = 20.69 V
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Example Circuit with Dependent Source
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30Ω
100mA
60Ω
10 V
15Ω
12Ω
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Example Circuit with Super Node
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Example Circuit with Super Node
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Introduction to Electrical & Computer Engineering
Mesh Analysis
• Lee Brinton
• Salt Lake Community College
18
Introduction to Electrical Engineering
Mesh Currents
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Loops Vs. Meshes
Branch Currents Vs. Mesh Currents
Mesh Analysis Process
Mesh Analysis with Dependent Sources
Supermeshes
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Loops Vs. Meshes
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Branch Currents Vs. Mesh Currents
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Loop Equations Involving Mesh Currents
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Steps to Performing Mesh Analysis
1. Identify meshes
2. Assign variable names to mesh currents
3. Write KVL equations around each mesh in terms of the
mesh currents
4. Solve the system of equations for the mesh currents
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Mesh-Current Example
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Super Mesh
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Super Mesh Example
15Ω
5Ω
2A
+
12 V
_
3Ω
10Ω
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Introduction to Electrical & Computer Engineering
Superposition
• Lee Brinton
• Salt Lake Community College
29
Superposition
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Superposition
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Introduction to Electrical & Computer Engineering
Thevenin and Norton Equivalent Circuits
• Lee Brinton
• Salt Lake Community College
32
Complex Circuit and Its Thevenin Equivalent
a
b
LM324 Operational Amplifier Circuit
Thevenin Equivalent Circuit
Of LM324
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Thevenin Equivalent
Power at the Shaft vs. Power at the Wheels
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Complex Circuit and Its Thevenin Equivalent
a
b
LM324 Operational Amplifier Circuit
Thevenin Equivalent Circuit
Of LM324
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Complex Circuit and Its Thevenin Equivalent
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Open Circuit Voltage and Short Circuit Current
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Determining the Thevenin Equivalent Circuit
R1
a
Vs
+
_
R2
b
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Determining the Thevenin Resistance
Method 1: Voc and Isc Method
R1
a
Vs
+
_
R2
b
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Determining the Thevenin Resistance
Method 2: Equivalent Resistance Method
R1
a
Vs
+
_
R2
b
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Determining the Thevenin Resistance
Method 3: Applying a Test Voltage
R1
a
Vs
+
_
R2
b
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Example Determining Thevenin Equivalent Circuit
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Thevenin Equivalent Circuit Example
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Thevenin Equivalent Circuit Example
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Introduction to Electrical & Computer Engineering
Maximum Power Transfer
• Lee Brinton
• Salt Lake Community College
45
Power Transfer to the Load
Maximize Voltage
Maximize Current
Maximize Power
RL >> Rth
RL << Rth
RL ?? Rth
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Maximum Power Transfer to the Load
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