Basic Concepts

1. Network Theory(19EC33)
2020-21
Class-1: Overview of Syllabus and Introduction to Network Theory
MOHANKUMAR V.
ASSISTANT PROFESSOR
D E P A R TM E N T O F E L E C TR O N I C S A N D C O M M U N I C A TI O N E N G I N E E R I N G
D R . A M B E D K A R I N S TI TU TE O F TE C H N O L O G Y , B E N G A L U R U - 5 6
E - M A I L : MO H A N K U MA R . V @ D R - A I T . O R G

2. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Overview of Syllabus
• Subject Title : Network Theory
• Subject code : 19EC33
• Credits: 04
• Total number of Contact hours : 52 hours
• Number of teaching hours per week: 04 hours
• 3- CIE’s, 25 marks each
• Final CIE=Sum of two best CIE marks and reduced it to 40 marks + 5 marks
Assignment + 5 marks Group Activity.
• Assignments – Problems
• Group Activity – PSPICE Simulation

3. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Overview of Syllabus…
Pre-requisites:
• Engineering Mathematics
• Basic Electrical Engineering
Objectives:
• Different types of Electrical Elements and their characteristics.
• Circuit Analysis Techniques such as Circuit simplification, loop analysis and node
analysis.
• Different Network Theorems and its applications,.
• Concepts of Resonance and its importance.
• Study of dynamic behavior(Transient and steady state response) of electrical systems
using initial conditions
• Applications of Laplace Transforms to electrical systems.
• Two port networks and its importance in the analysis of electrical circuits.

4. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Overview of Syllabus…
Contents:
Unit-I:
Ch-1: Basic Circuit Concepts
Unit-II:
Ch-1: Network Theorems
Ch-2: Resonant Circuits
Unit-III:
Ch-1: Transient Behaviour and Initial Conditions
Unit-IV:
Ch-1: Laplace Transforms
Unit-V:
Ch-1: Two Port Network Parameters

5. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Overview of Syllabus…
Outcomes:
• Apply the network reduction techniques to simplify the electrical circuits and analyze
electrical circuits using loop and nodal analysis.
• Apply the network theorems to find the load quantities, explain the resonant
parameters and the analyze the circuit.
• Explain and find the transient behavior of electrical circuits with initial conditions.
• Apply the Laplace Transforms for the analysis of electrical circuits.
• Define, explain and find the two port network parameters of electrical circuits and
derive the relationship between one parameter to other parameter.
Pre-Requisite for:
• Electronic Circuits
• Communications
• Power Electronics

6. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Overview of Syllabus…
• Text Books:
• Charles K Alexander and Mathew N O Sadiku, “Fundamentals of
Electric Circuits”, 3rd edition, Tata McGraw-Hill, 2009.

7. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Introduction
Definition: Network Theory
Theory: A set of Principles or Ideas are used to perform an activity (
In this context activity is to study and analysis of a Networks).
Network ( Electrical ): Interconnection or combination of electrical
elements is called an electrical network, generally network.
Network Theory: Set of principles or ideas are used to study the
behaviour of electrical networks.
Circuit and Network:
Network- Open loop or Closed Loop
Circuit- Closed Loop
All circuits are networks but all networks are not circuits
Network
Network/Circuit

8. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Introduction…
Electrical Elements
Electrical Elements
Passive
Elements
Resistors Capacitors Inductors
Active
Elements
Independent
sources
Ideal
Voltage Current
Practical
voltage current
Dependent sources
VCVS VCIS ICVS ICIS

9. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Introduction…
Basic principles
1. Current: Rate of change of Charge is called current, it is denoted as “I” and unit is Amperes.
𝐼 =
𝑑𝑄
𝑑𝑡
1. Voltage: Rate of change of Flux is called Voltage, it is denoted as “V” and unit is volts.
𝑉 =
𝑑Ø
𝑑𝑡
1. Power: Product of Voltage and Current is called Power, it is denoted as “P” and unit is watts.
𝑃 = 𝑉 × 𝐼
Branch: A Path of element is connecting between two nodes is called Branch.
Node: Two or more elements connected at a Point/Junction is called as a Node.
Ohm’s law: Ohm’s law states that the voltage across an element is directly proportional to the current
flowing through that element.
𝑖. 𝑒., 𝑉𝛼 𝐼

10. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Introduction…
Passive Elements
1. Resistor[R]:
•A resistor opposes the flow of electric current.
•Resistors dissipate energy in the form of heat.
•Resistors exhibit negative temperature effects.
•Obeys ohm’s Law
VαI, V=R I ohms.
Where, R is the Proportionality constant called Resistance measured
in Ohms, V is the Voltage and I is the Current.
•If Resistors are connected in Series. 𝑅 𝑒𝑞 = 𝑖=1
𝑛
𝑅𝑖
•If Resistors are connected in Parallel.
1
𝑅 𝑒𝑞
= 𝑖=1
𝑛 1
𝑅 𝑖
•Power 𝑃 = 𝑉𝑥𝐼 ⇒
𝑉2
𝑅
⇒ 𝐼2 𝑅 𝑊𝑎𝑡𝑡𝑠
Circuit Symbol
R
Resistors are in Series
Resistors are in Parallel

11. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Introduction…
Resistors are connected in Star form. Resistors are connected in Delta form.
 Star to Delta conversion
𝑅 𝑎 =
𝑅1 𝑅2+𝑅2 𝑅3+𝑅1 𝑅3
𝑅1
; 𝑅 𝑏 =
𝑅1 𝑅2+𝑅2 𝑅3+𝑅1 𝑅3
𝑅2
; 𝑅 𝑐 =
𝑅1 𝑅2+𝑅2 𝑅3+𝑅1 𝑅3
𝑅3
.
 Delta to Star conversion
𝑅1 =
𝑅 𝑏 𝑅 𝑐
𝑅 𝑎+𝑅 𝑏+𝑅 𝑐
; 𝑅2 =
𝑅 𝑎 𝑅 𝑐
𝑅 𝑎+𝑅 𝑏+𝑅 𝑐
; 𝑅3 =
𝑅 𝑎 𝑅 𝑏
𝑅 𝑎+𝑅 𝑏+𝑅 𝑐
.

12. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Introduction…
2. Capacitor [C]:
• Capacitors stores energy in the form of Electrostatic Field.
• 𝑄 = 𝐶𝑉
• v(t)=
1
𝐶
𝑖 𝑡 . 𝑑𝑡; i t = C
dv t
dt
.
• 𝐸 =
1
2
𝐶𝑉2
Joules.
• 𝐶𝑒𝑞 =
1
𝑖=1
𝑛 1/𝐶 𝑖
; If the Capacitors are connected in Series.
• 𝐶𝑒𝑞 = 𝑖=1
𝑛
𝐶𝑖 ; If the Capacitors are connected in Parallel.
• Star to delta and delta to star conversion is applicable to capacitors,
only if it is in Reactance form.
• Capacitive Reactance 𝑋 𝐶 =
1
2𝜋𝑓𝐶
Ohms.
Circuit Symbol
C

13. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Introduction…
3. Inductor [L]:
• Inductors stores energy in the form of Electro Magnetic Field.
• 𝜑 = 𝐿𝐼
• v(t)= L
di t
dt
; i t =
1
𝐿
𝑣 𝑡 . 𝑑𝑡.
• 𝐸 =
1
2
𝐿𝐼2
Joules.
• 𝐿 𝑒𝑞 = 𝑖=1
𝑛
𝐿𝑖 ; If the Inductors are connected in Series.
• 𝐿 𝑒𝑞 =
1
𝑖=1
𝑛 1/𝐿 𝑖
; If the Inductors are connected in Parallel.
• Star to delta and delta to star conversion applicable to Inductors
also, only if it is in Reactance form.
• Inductive Reactance, 𝑋 𝐿 = 2𝜋𝑓𝐿 Ohms.
Circuit Symbol
L

14. Dept. of ECE, Dr. Ambedkar Institute of Technology, Bengaluru
Network Theory (19EC33)
Disclaimer
Some Contents and Images showed in this PPT
have been taken from the various internet
sources for educational purpose only.
Thank You
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