Two-Port Networks
Part I
Dr. Mohamed Refky Amin
Electronics and Electrical Communications Engineering Department (EECE)
Cairo University
http://scholar.cu.edu.eg/refky/
OUTLINE
• Introduction
• The Impedance (Z) Parameters
• The Admittance (Y) Parameters
• The Hybrid (H) Parameters
• The Transmission (A) Parameters
• Relationships Between Parameters
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Introduction
Port: A pair of terminals through
which a current may enter or leave
a network.
Definitions
Two-terminal devices or elements (such as resistors, capacitors,
and inductors) result in one-port networks.
The current entering one terminal leaves through the other
terminal so that the net current entering the port equals zero.
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Introduction
Two-port networks: (a four-terminal network) is an electrical
network with two separate ports for input and output.
Definitions
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Introduction
Solving by using loop analysis
Two-port Networks
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Loop (1)
Loop (2)
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Introduction
Solving by using loop analysis
Two-port Networks
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Loop (1)
Loop (2)
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Introduction
Two-port Networks
The various terms that relate
these voltages and currents are
called parameters.
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Introduction
Two-port Networks
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We assume that the two-port
networks (Linear networks)
contain no independent sources.
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Two-port networks
Types of Network Parameters:
• Z-Parameters (Impedance Parameters)
• Y-Parameters (Admittance Parameters)
• H-Parameters (Hybrid Parameters)
• A-Parameters (Transmission Parameters)
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Two-port networks
Types of Network Parameters:
• Z-Parameters (Impedance Parameters)
• Y-Parameters (Admittance Parameters)
• H-Parameters (Hybrid Parameters)
• A-Parameters (Transmission Parameters)
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Two-port networks
Z-Parameters
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Two-port networks
Z-Parameters
Open-circuit transfer impedance from port 2 to port 1
Open-circuit input impedance
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Two-port networks
Z-Parameters
Open-circuit output impedance
Open-circuit transfer impedance from port 1 to port 2
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Two-port networks
Example (1)
Compute the Z-parameters for the shown circuit
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Two-port networks
Z-Parameters - Equivalent Circuit
Model with two dependent voltage sources Dr. Mohamed Refky 15
Two-port networks
Z-Parameters - Network Properties
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Two-port networks
Z-Parameters - Network Properties
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Two-port networks
Y-Parameters
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Two-port networks
Y-Parameters
Short-circuit transfer admittance from port 2 to port 1
Short-circuit input admittance
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Two-port networks
Y-Parameters
Short-circuit output admittance
Short-circuit transfer admittance from port 1 to port 2
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Two-port networks
Z-Parameters and Y-Parameters
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From the Z-Parameters
From the Y-Parameters
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Two-port networks
Example (2)
Compute the Y-parameters for the shown circuit
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Two-port networks
Y-Parameters - Equivalent Circuit
Model with two dependent current sources Dr. Mohamed Refky 23
Two-port networks
Y-Parameters - Network Properties
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Two-port networks
H-Parameters
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Two-port networks
H-Parameters
Short-circuit forward current gain
Short-circuit input impedance
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Two-port networks
H-Parameters
Open-circuit output admittance
Open-circuit reverse voltage gain
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Two-port networks
H-Parameters - Equivalent Circuit
Model with two dependent sources Dr. Mohamed Refky 28
Two-port networks
H-Parameters - Network Properties
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Two-port networks
A-Parameters
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Two-port networks
A-Parameters
Open-circuit transfer admittance
Open-circuit voltage ratio
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Two-port networks
A-Parameters
Negative short-circuit current ratio
Negative short-circuit transfer impedance
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Two-port networks
A-Parameters - Network Properties
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Two-port networks
Relationships Between Parameters
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Two-port networks
Relationships Between Parameters
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Two-port networks
Relationships Between Parameters
Z-parameters and H-parameters
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Two-port networks
Relationships Between Parameters
Z-parameters and H-parameters
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Two-port networks
Relationships Between Parameters
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Two-port networks
Relationships Between Parameters
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Two-port networks
Relationships Between Parameters
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Two-port networks
Z
Y
H
A
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