INTRODUCTION TO ELECTRICAL CIRCUITS
Network theory is the study of solving the problems of electric circuits or electric networks. In this introductory chapter, let us first discuss the basic terminology of electric circuits and the types of network elements.
Basic Terminology In Network Theory, we will frequently come across the following terms --
▪︎Electric Circuit
▪︎ Electric Network
▪︎Current
▪︎Voltage
▪︎Power
So, it is imperative that we gather some basic knowledge on these terms before proceeding further. Let’s start with Electric Circuit.
Electric Circuit
An electric circuit contains a closed path for providing a flow of electrons from a voltage source or current source. The elements present in an electric circuit will be in series connection, parallel connection, or in any combination of series and parallel connections.
Electric Network
An electric network need not contain a closed path for providing a flow of electrons from a voltage source or current source. Hence, we can conclude that "all electric circuits are electric networks" but the converse need not be true.
Current
The current "I" flowing through a conductor is nothing but the time rate of flow of charge.Mathematically, it can be written as Where,
▪︎ Q is the charge and its unit is Coloumb.
▪︎ t is the time and its unit is second.
As an analogy, electric current can be thought of as the flow of water through a pipe. Current is measured in terms of Ampere. In general, Electron current flows from negative terminal of source to positive terminal, whereas, Conventional current flows from positive terminal of source to negative terminal.Electron current is obtained due to the movement of free electrons, whereas, Conventional current is obtained due to the movement of free positive charges. Both of these are called as electric current.
Voltage
The voltage "V" is nothing but an electromotive force that causes the charge (electrons) to
flow. Mathematically, it can be written as
Where,
▪︎ W is the potential energy and its unit is Joule.
▪︎ Q is the charge and its unit is Coloumb.
As an analogy, Voltage can be thought of as the pressure of water that causes the water to flow through a
pipe. It is measured in terms of Volt.
Power
The power "P" is nothing but the time rate of flow of electrical energy. Mathematically, it
can be written as
Where,
▪︎W is the electrical energy and it is measured in terms of Joule.
▪︎ t is the time and it is measured in seconds.
We can re-write the above equation a
Therefore, power is nothing but the product of voltage V and current I. Its unit is Watt.
Types of Network Elements
We can classify the Network elements into various types based on some parameters.
Following are the types of Network elements −
▪︎Active Elements and Passive Elements
▪︎Linear Elements and Non-linear Elements
▪︎Bilateral Elements and Unilateral Elements
▪︎ Lumped Elements and Distributed Elements
Tags:
electrical
