Electronics

# Network Theory – A Complete Guide For Gate Preparation

### What is Network Analysis in Network theory?

In the Network theory, Network analysis is the main thing to be considered that, When any structured circuit is complicated, then analysis for current, voltage, power or frequency performances becomes difficult.

In simple words, the Network analysis is the technique that used to analyze any structured circuit in an easy manner is known as Network Analysis.

## Basic Terminology of Network Theory

So you will definitely fell love with this Chapter “Network Theory” after knowing, how can we estimate the network analysis.

Before that, we will just say “Hello” to these basics, which are already known us.

• Electric Network
• Current
• Electric Circuit
• Voltage
• Power

### *Electric Circuit

An Electric circuit is designed in the closed path to allow the flow of electrons from a current source or a voltage source.

In the electric circuit, the elements are in the form of parallel connection, series connection or in the combination of parallel and series connection.

Example:

Consider the above electric circuit, that has closed path.

### *Electric Network

An Electric network is not always necessary to be in the closed path for proving a flow of electrons.

So, here we can say that

All Electric circuits are Electric networks

### *Current

The flow of electric charge in a circuit or in a conductor is known as electric current.

In the electric circuit, this charge is generally carried by moving electrons in the wire.

Where current is denoted as I

Mathematically the current can be written as

I=dQ/dT

Where,

• Q is the charge and its unit is Coloumb.
• t is the time and its unit is second.

Where

Electric Current is measured in the terms of Ampere.

In a general way the electric current, we can say that water(electric current) that flows through the pipeline(wire).

### **Electron Current

However, the electron current generally flows from the negative end of the source to the positive end of the source.

That means the electron current travels from negative terminal to the Positive terminal of the source.

The movement of free electrons obtains the Electron current.

In the above image, see the green line indicates the electron current flow, from the negative terminal to positive terminal.

### **Conventional Current

Conventional is totally opposite to the electron current, that this conventional current flows from positive end of the source to the negative end of the source.

However, the electron current generally flows from the negative end of the source to the positive end of the source.

The movement of free positive charges obtains the Conventional current.

In the above image, see the red line indicates the Conventional current flow, from the positive terminal to negative terminal.

### *Voltage

In simple words, Voltage is nothing but a regulator, that controls how much current to flow.

In Technical words, Voltage is nothing but an electromotive force, which causes the charge to flow.

The Voltage is denoted as V. Its SI unit is Volt.

And it can be mathematically written as

V=dW/dQ

Where,

• W is the potential energy and its unit is Joule.
• Q is the charge and its unit is Coloumb.

### *Power

In simple words, power is a measurement device, it measures, electrons flown in particular amount of time.

In Technical words, the power is rate of flow of energy per unit time in an electric circuit is known as Power.

The Power is denoted as P

And it can be mathematically written as

P=dW/dt

Where,

• W is electrical energy and measured in terms of the joule.
• is time and measured in seconds.

By Considering the Above equation, we can rewrite the above equation

P = (dW/dt) = (dW/dQ*dQ/dt) = VI

So here comes the conclusion, that power is nothing but the product of current and Voltage V. Where it’s SI unit is Watt.

## Types of Network Elements

The next thing we have to study is Network Elements.

So in this, based on some parameters, we will discuss Network elements in various types.

These are the Types of Network Elements

• Active Elements and Passive Elements
• Linear Elements and Non-linear Elements
• Bilateral Elements and Unilateral Elements

### Active Elements and Passive Elements

Based on the delivering power, we classify the network elements into Active Elements and Passive Elements.