EE_10_F07_Lecture 4 - UCLA ELECTRICAL ENGINEERING...

UCLA E
LECTRICAL
E
NGINEERING
D
EPARTMENT
: EE 10: C
IRCUIT
A
NALYSIS
1
L
ECTURE
4
LECTURE NOTES: OCT. 15, 2007
OUTLINE
REVIEW ........................................................................................................................................ 2
CIRCUIT ANALYSIS: THE NODE-VOLTAGE AND MESH-CURRENT METHODS ..... 3
IMPORTANT DEFINITIONS OF CIRCUIT FEATURES ...................................................... 3
THE NODE-VOLTAGE CIRCUIT ANALYSIS METHOD INTRODUCTION ................... 6
PROBLEM SOLVING APPROACH WITH NODE VOLTAGE METHOD ......................... 6
EXAMPLE NODE-VOLTAGE CIRCUIT SOLUTION ........................................................... 9
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UCLA E
LECTRICAL
E
NGINEERING
D
EPARTMENT
: EE 10: C
IRCUIT
A
NALYSIS
1
L
ECTURE
4
REVIEW
1) Fundamental Resistor Circuits
a. Series Resistor Circuits
b. Parallel Resistor Circuits
2) The Voltage Divider
3) The Current Divider
4) The Digital to Analog Converter
5) The Wheatstone Bridge Circuit
6) Resistor Circuit Transformations
2

UCLA E
LECTRICAL
E
NGINEERING
D
EPARTMENT
: EE 10: C
IRCUIT
A
NALYSIS
1
L
ECTURE
4
CIRCUIT ANALYSIS: THE NODE-VOLTAGE AND MESH-CURRENT METHODS
• Given our background with Kirchhoff’s Laws, Ohm’s Law, and the series and
parallel equivalent circuit methods, we are now prepared to introduce a set of
new analysis methods.
• First, we need a set of rules that provide the guidance for selecting the circuit
paths that produce the most rapidly obtained solution.
• An important circuit concept of a reference potential leads to a new analysis
method, the node-voltage method. This is used throughout circuit analysis and
is important in the intuition for circuit design.
• The node-voltage analysis method, as we will see, is particularly applicable to
systems that contain many parallel elements.
• We will also learn about the mesh-current method. This is a powerful technique
that is applicable to circuits that contain many series elements.
• As we make progress, we will become increasingly capable of solving circuit
problems and developing the intuition and visualization for circuit design.
IMPORTANT DEFINITIONS OF CIRCUIT FEATURES
• A set of new circuit rules will rely on definitions of:
o nodes (connecting 2, 3, or more elements)
o and paths (open and closed).
• This set of definitions is shown below.
Node
The intersection between two or more circuit elements
Essential Node
The intersection between three or more elements
Path
A continuous line segment passing through adjacent circuit
elements that passes through circuit elements only once.
Branch
A path that connects two nodes
Essential Branch
A path that connects two essential nodes without crossing other
essential nodes
Loop
A closed path – a path that starts and ends at the same node
without passing through any other node more than once
Mesh
A loop that does not enclose any other loops. This important
term derives from the appearance of circuits that are drawn
with these loops superimposed.
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