# Introduction to Two-Port Networks

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ALL ABOUT ELECTRONICS. So, in this video, we will learn about the

Two-Port Network. So, as its name suggests, the two-port network

is the electrical circuit or the network which contains the two ports. But to understand it in detail, first of all,

we need to understand what is port? So, the port is the pair of two terminals

which connect the electrical circuit or the network to the external circuit. So, through this port, any external network

or any independent source can be connected to the existing network. But any two terminals can not be called as

a port. And for that, they need to satisfy the port

condition. That means if the current I enter through

the one terminal of the port, then the same current should leave through the second terminal

of the port. So, If the pair of terminals satisfy this

condition then they can be called as a port. So, if the circuit or the electrical network

contains one such port then it is called the one-port network. And all the basic circuit elements, like,

the resistor, the capacitor, and the inductor are the examples of the one-port network. Similarly, if the electrical circuit or the

network contains two such ports then it is called the two-port network. And this simple T- network is an example of

the two-port network. So, here these two terminals will act as one

port, while these other two terminals will act as a second port. Similarly, if the network contains more than

two ports then it is called the multi-port network. And the directional couplers and the circulators

are the examples of the multiport network. But in this video, as well as in the upcoming

videos, we will focus on the two-port network. So, in the two-port network, this port 1 is

often considered as the input port, while the second port is considered as the output

port. And many times when the circuit or the network

is represented using the port, then it reduces the complexity during the circuit analysis. So, this two-port network model is used in

mathematical circuit analysis techniques for complex circuits. So, using this two-port network model, we

can isolate the portion of the larger circuits. So, here basically this two-port network is

regarded as the black box. And the property of this network is specified

by some parameters. So, when some input signal is applied to this

port, then the response of this network can be easily found using these network parameters. And in this case, we do not need to find the

internal voltage and current of this network. That means using this two-port network model,

we can analyze the complex circuits easily. Apart from that, using this two-port network

model, a similar type of device or the circuits can be compared easily. For example, the transistor is often regarded

as the two-port device for the small-signal analysis. And during the analysis, it is characterized

by the network parameters. So, in general, any circuit with two pairs

of terminals can be regarded as a two-port network, provided it does not contain independent

sources and it also satisfies the port condition. So, the filters, transformers, the transmission lines and the small-signal model of a transistor are the few examples where they

are treated as a two-port network during the circuit analysis. So, in this two-port network, let’s say

the voltage across the port-1 is equal to V1, while the current which is flowing through

port 1 is I1. Similarly, let’s say the voltage across

the port-2 is equal to V2 and the current which is flowing through this port 2 is equal

to I2. So, here basically there are four variables. That is V1, I1, V2, and I2. And for the analysis, out of the four variables, the two variables are

considered as the independent variables while the remaining two variables are the dependent

variables. for example, let’s say, here I1, and I2 are

the independent variables, while the V1 and V2 are the dependent variables. That means this V1 and V2 can be expressed

in terms of the independent variables I1 and I2. And based on which variables are the independent

variables, the six different models or the six different parameters can be defined for

this two-port network. So, here is the list of the different two-port

parameters. So, in the upcoming videos, we will learn

about all these different types of parameters. And we will also solve some problems based

on these two-port parameters. So, I hope in this video, you understood what

is two-port network and what is the significance of this two-port network. So, if you have any questions or suggestions,

do let me know here in the comment section below. If you like this video, hit the like button

and subscribe to the channel for more such videos.

The timestamps for the different topics covered in the video:

0:20 What is Port? What is Two-Port Network?

1:12 One-Port, Two-Port, and Multi-Port Network

2:10 Importance of Two-Port Network Model

VCO IC NE566/NE565 Pe Video Banaiye Sir Plzzz.

Sir pura two port kab tak finish karoge

nice explanation sir. please upload series videos on network analysis.