This PPT explains Basic electric circuit laws

1. 20EEG01 - BASIC ELECTRICAL
AND ELECTRONICS
ENGINEERING
By
R.Kanmani,
AP(Sr.Gr)/ECE
SRIT

2. Course Objective
The course aims to provide the basic principles of
electric circuits, electron devices, electrical wiring
and AC/DC machines for applications in real time
engineering problems.

3. Course Content
Electric circuits and Domestic Wiring
Ohm’s Law and Kirchhoff’s laws - series and parallel
circuits, equivalent resistance- Mesh and Nodal
Analysis (Analysis with only independent source and
DC circuits)- Superposition theorem, Thevenin’s
theorem, Norton’s theorem. Types of wiring- Domestic
wiring - Specification of Wires – Importance of
Earthing.
AC Circuits
Concepts of AC circuits –RMS value, average value,
form and peak factors. Power relations in single
phase and three phase circuits- real and reactive
power – power factor, Star connection – Delta
connection –Balanced Loads.

4. Course Content
Electrical Machines
Construction, Principle of operation and characteristics of DC
separately excited generator and DC Shunt and Series motor,
EMF equation of DC separately excited generator and Torque
equation of DC Shunt and Series motor- applications.
Construction and Principle of operation of transformer, EMF
Equation- applications. Construction and Principle of operation
of synchronous Motor. Construction and Principle of operation
of single phase Induction motor - applications.
Semiconductor Devices and Applications
Introduction to semiconductors- PN junction diode - forward
and reverse bias characteristics –Zener diode and its
characteristics. Operation of Half wave and Full wave rectifiers –
Capacitive filters- Zener diode Voltage regulators

5. Course Content
Current Controlled Devices
Operation of PNP and NPN transistors - Early effect –
Input and Output Characteristics of CB, CE, CC
Configurations , Working principle and
characteristics of SCR, UJT.

6. References
1. A Fitzgerald , Charles Kingsley , Stephen Umans,
“Electric Machinery”, 7th Edition, McGraw-Hill,
2013.
2. Robert Boylestad, Louis Nashelsky, “Electronic
Devices and Circuit Theory”, Prentice Hall, 11th
Edition 2015.
3. V K Mehta, Rohit Mehta , “ Principles of Electronics”,
11 th edition, S Chand Publishing company ,
2016.
4. Mahmood Nahvi, Joseph A Edminister, “Electric
Circuits”, McGraw-Hill Education, 5th Edition, 2010.
5. Bhattacharya.S.K, “Basic Electrical and Electronics
Engineering”, 1st Edition, Pearson Education, 2011

7. Course Outcomes
CO1: Ability to understand the basic
concepts of electric circuits, electronic
devices &circuits and electric machines
CO2: Ability to understand the concepts
related with electrical domestic wiring
CO3: Ability to apply the concepts of
electrical machines for industrial
applications
CO4: Ability to analyze the characteristics
of electronic devices and circuits

8. Ohm’s Law
Ohm’s law states that the voltage or potential
difference between two points is directly
proportional to the current
or electricity passing through the resistance,
and directly proportional to the resistance of
the circuit. The formula for Ohm’s law is
V=IR. This relationship between current,
voltage, and relationship was discovered by
German scientist Georg Simon Ohm.

9. Georg Simon Ohm

10. Most basic components of electricity are
voltage, current, and resistance. Ohm’s
law shows a simple relation between these
three quantities. Ohm’s law states that
the current through a conductor between
two points is directly proportional to the
voltage across the two points.

11. Ohm’s Law Formula
Voltage= Current× Resistance
V= I×R
V= voltage, I= current and R= resistance
The SI unit of resistance is ohms and is
denoted by Ω
This law is one of the most basic laws of
electricity. It helps to calculate
the power, efficiency, current, voltage,
and resistance of an element of an
electrical circuit.

12. Limitations of Ohm’s Law
 Ohm’s law is not applicable to unilateral
networks. Unilateral networks allow the
current to flow in one direction. Such types of
network consist elements like
a diode, transistor, etc.
 Ohm’s law is also not applicable to non –
linear elements. Non-linear elements are
those which do not have current exactly
proportional to the applied voltage that
means the resistance value of those elements
changes for different values of voltage and
current. Examples of non – linear elements
are the thyristor.

13. Uses of Ohm’s Law
 The basic quantities of electricity are the
current, voltage and resistance. Ohm’s Law
establishes a simple equation between the
three quantities, serving as the most basic
law of electricity.
 Ohm’s law helps in calculating the power,
efficiency and the impedance of any element
of the electrical circuit.
 It helps in determining the voltage, current or
resistance of a linear circuit when either of
the two quantities is known.

14. Kirchhoff’s First Law – The
Current Law, (KCL)
Kirchhoff’s Current Law or KCL, states
that the “total current or charge entering a
junction or node is exactly equal to the
charge leaving the node as it has no other
place to go except to leave, as no charge is
lost within the node“. In other words the
algebraic sum of ALL the currents entering
and leaving a node must be equal to zero,
I(exiting) + I(entering) = 0. This idea by Kirchhoff
is commonly known as the Conservation
of Charge.

15. We can use Kirchhoff’s current law
when analyzing parallel circuits.

16. Kirchhoff’s Second Law – The
Voltage Law, (KVL)
Kirchhoff’s Voltage Law or KVL, states
that “in any closed loop network, the
total voltage around the loop is equal to
the sum of all the voltage drops within
the same loop” which is also equal to
zero. In other words the algebraic sum
of all voltages within the loop must be
equal to zero. This idea by Kirchhoff is
known as the Conservation of Energy.

17. Starting at any point in the loop continue
in the same direction noting the direction
of all the voltage drops, either positive or
negative, and returning back to the same
starting point. It is important to maintain
the same direction either clockwise or
anti-clockwise or the final voltage sum will
not be equal to zero. We can use
Kirchhoff’s voltage law when analyzing
series circuits.

18. Common circuit theory terms
Circuit – a circuit is a closed loop conducting path in which
an electrical current flows.
Path – a single line of connecting elements or sources.
Node – a node is a junction, connection or terminal within a
circuit were two or more circuit elements are connected or
joined together giving a connection point between two or
more branches. A node is indicated by a dot.
Branch – a branch is a single or group of components such
as resistors or a source which are connected between two
nodes.
Loop – a loop is a simple closed path in a circuit in which no
circuit element or node is encountered more than once.
Mesh – a mesh is a single closed loop series path that does
not contain any other paths. There are no loops inside a
mesh.