BASIC ELECTRICAL ENGINEERING DC CIRCUITS UNIT 1 PART 1 NOTES

BASICS OF ELECTRICAL
ENGINEERING (1ST YEAR)
INTRODUCTION TO
“FUNDAMENTAL OF ELECTRICITY”
(सरल भाषा में)
LEC#01
Prof. Prasant Kumar BEEE 1

FUNDAMENTAL OF
ELECTRICITY
LEC # 02

1. Atom Model
Atoms consist of a nucleus
made of protons and
neutrons orbited by
electrons.
Atoms are the basic building
block of all matters
BASICS OF ELECTRICITY

Fundamental of Electricity
2. Atom
• Protons
• Neutrons
• Electrons
“Each atom has the same number of protons
and electrons.”

3. Proton and Electron
Protons carries positive charge
– It is relatively large mass
– Does not play active part in
electrical current flow
Electrons carries negative charge
– Light mass
– Play an important role in electrical current flow
Fundamental of ElectricityBASICS OF ELECTRICITY

4. Unit of Charge
• Unit of Charge is called Coulomb (C)
• An electron and a proton have exactly
same amount of charge
• One coulomb of charge is equal to
approximately 628 x 1016 electron charge
Weeks 1 ~ 2

5. Free Electrons
Free Electrons
Applying Heat or Light

6. Electrical Materials
All material may be classified into three
major classes:
• Conductors (copper, aluminum, siliver,
platinum, bronz, gold)
• Insulators (glass, rubber, plastic, air,
varnish, paper, wood, mica, ceramic,
certain oils)
• Semiconductors (germanium, silicon)

6. Electrical Materials
• Conductors have many free electrons
which will be drifting in a random
manner within the material
• Insulators have very few free electrons
• Semiconductors falls somewhere between
these two extremes

BASICS OF ELECTRICAL ENGINEERING
What is Electric CURRENT?
विद्युत प्रिाह क्या है?
Definition,Properties,Unit
LEC#02

❖ Electric current is the movement, or flow of
electrons through a conductive material.
Fundamental of ElectricityWHAT IS ELECTRIC CURRENT ?

Fundamental of ElectricityFORMULA & UNIT OF ELECTRIC CURRENT
❖ The electric current is the rate of charge flow i.e. charge/time.
❖ Since the charge is measured in coulombs & time in seconds
❖ The unit of electric current becomes coulombs/sec.
❖ The SI unit of electric current is Ampere (A).
Electric Current (I) = Charge (Q) / Time (t)

Fundamental of ElectricityCONVENTION OF CURRENT FLOW

Fundamental of ElectricityTYPES OF CURRENT
CURRENT
AC DC

❖ The type of electric current whose direction changes
continuously throughout the time is called
alternating current or AC.

❖ The direct current is a type of
electric current whose direction
does not change &
conventionally.
❖ It flows from the positive
terminal of the battery to the
negative terminal of the battery.

17Prof. Prasant Kumar BEEE
THANKS TO ALL
FOR ANY PROBLEN FEEL FREE TO VISIT YOUTUBE
FOR DETAIL UNDERSTANDING @.

Electromotive Force (EMF),Electric
Potential & Potential Difference
में समानता और अंतर.
LEC#03

Fundamental of ElectricityELECTROMOTIVE FORCE (EMF)

Fundamental of ElectricityROLE OF EMF IN CIRCUIT

❖ Typical sources of emf are cells, batteries and
generators.
❖ The amount of current that will flow through a
circuit is related to the size of the emf applied to
it.
SOURCES OF EMF
Higher Potential Lower Potential

ELECTRIC POTENTIAL
❖ An electric potential is also called the electric field potential,
potential drop, or the electrostatic potential.
❖ “It is the amount of work needed to move a unit of electric charge
from a reference point to a specific point in an electric field
without producing an acceleration”.

ELECTRIC POTENTIAL

ELECTRIC POTENTIAL DIFFERENCE
❖ The electric potential difference between points A and B, is
VB−VA, is defined to be the change in potential energy
of a charge q moved from A to B, divided by the
charge.
❖ Unit of potential difference is joules per coulomb, given
the name volt (V) after Alessandro Volta.
1V = 1 J/C

ΔV=VB−VA=+12V

ELECTRICAL SOURCE AND TYPES
विद्युत स्रोत के प्रकार
VOLAGE,CURRENT,IDEAL&PRACTICAL SOURCE
LEC#04

ELECTRIC SOURCE
An electrical supply or simply, “a source”, is a device that “supplies
electrical power to a circuit in the form of a voltage source or a
current source”.

ELECTRIC SOURCE
SOURCE
DC SOURCE
INDEPENDENT
SOURCE
DEPENDENT
SOURCE
AC SOURCE

TYPES OF ELECTRIC SOURCE

AC SOURCE & DC SOURCE
क्या है?
समानता और अंतर
LEC#05

AC SOURCE
❖ Alternating current (ac) is the flow of electric charge that
periodically reverses direction.

AC SOURCE

DC SOURCE
❖ DC sources refer to sources of electrical energy which are
associated with constant voltages and currents.
❖ Direct current is the one directional or unidirectional flow
electric charge.

DC SOURCE

SYMBOL OF VOLTAGE SOURCE

SYMBOL OF CURRENT SOURCE

COMPARISION BETWEEN AC & DC SOURCE

DEPENDENT SOURCE &
INDEPENDENT SOURCE क्या
है?
LEC#06

ELECTRIC SOURCE
SOURCE
DEPENDENT
SOURCE
Voltage control
voltage source
(VCVS)
Voltage control
current source
(VCCS)
current control
voltage source
(CCVS)
current control
current source
(CCCS)
INDEPENDENT
SOURCE

INDEPENDENT SOURCE
❖ In the theory of electrical networks, an independent source is a
voltage source or a current source whose value does not depend on a
voltage or current elsewhere in the network.
❖ An independent voltage/current source is an idealized circuit component that
fixes the voltage or current in a branch, respectively, to a specified value.

DEPENDENT SOURCE
❖ In the theory of electrical networks, a dependent source is a
voltage source or a current source whose value depends on a voltage or
current elsewhere in the network.
❖ Dependent sources are useful, for example, in modeling the behavior of
amplifiers.

VOLTAGE CONTROLLED VOLTAGE SOURCE (VCVS)
❖ The source delivers the voltage as per the voltage of the dependent element.

VOLTAGE CONTROLLED VOLTAGE SOURCE (VCVS)
SYMBOL OF VCVS

DEPENDENT SOURCEVOLTAGE CONTROLLED CURRENT SOURCE (VCCS)
❖ The source delivers the current as per the voltage of the dependent
element.

DEPENDENT SOURCEVOLTAGE CONTROLLED CURRENT SOURCE (VCCS)
SYMBOL OF VCCS

DEPENDENT SOURCECURRENT CONTROLLED CURRENT SOURCE (CCCS)
❖ The source delivers the current as per the current of the dependent
element.

CURRENT CONTROLLED CURRENT SOURCE (CCCS)
SYMBOL OF CCCS

DEPENDENT SOURCECURRENT CONTROLLED VOLTAGE SOURCE (CCVS)
❖ The source delivers the voltage as per the current of the dependent
element.

DEPENDENT SOURCECURRENT CONTROLLED VOLTAGE SOURCE (CCVS)
SYMBOL OF CCVS

DEPENDENT SOURCEEXAMPLE OF DEPENDENT & INDEPENDENT SOURCE

VOLTAGE SOURCE &
CURRENT SOURCE क्या है?
CIRCUIT DIAGRAM & SYMBOL
LEC#07 IN हहंINGLISH

SOURCE & TYPES
ELECTRICAL
SOURCE
Voltage Source
Ideal Voltage
Source
Practical
Voltage Source
Current Source
Ideal Current
Source
Practical
Current Source

DEPENDENT SOURCEVOLTAGE SOURCE
❖ A voltage source, such as a battery or generator, provides a potential
difference (voltage) between two points within an electrical circuit
allowing current to flowing around it.
IDEAL VOLTAGE SOURCE PRACTICAL VOLTAGE SOURCE

DEPENDENT SOURCECURRENT SOURCE
❖ A current source is an electronic circuit that delivers or absorbs
an electric current.
❖ A current source is the dual of a voltage source.
IDEAL CURRENT SOURCE PRACTICAL CURRENT SOURCE

IDEAL VOLTAGE SOURCE &
PRACTICAL VOLTAGE
SOURCE क्या है?

DEPENDENT SOURCEIDEAL VOLTAGE SOURCE
❖ A voltage source is a two-terminal device whose voltage at any instant of
time is constant and is independent of the current drawn from it.
Internal Resistance
Rin = 0 ohm

DEPENDENT SOURCEPRACTICAL VOLTAGE SOURCE
❖ A Practical voltage source is a compound of two ideal components:
1. An ideal voltage source
2. A series resistor
V=VS− I.RS

COMPARE IDEAL & PRACTICAL VOLTAGE SOURCE

IDEAL CURRENT SOURCE &
PRACTICAL CURRENT
SOURCE क्या है?
LEC#09

DEPENDENT SOURCEIDEAL CURRENT SOURCE
❖ An ideal current source generates a current that is independent of the
voltage changes across it.
❖ It has infinite resistance.
Rin= ∞Ω

DEPENDENT SOURCEPRACTICAL CURRENT SOURCE
❖ A practical current source is represented as an ideal current source
connected with the resistance in parallel.
❖ Internal Resistance is connected in parallel with ideal current source.
Rin

DEPENDENT SOURCECOMPARE IDEAL & PRACTICAL CURRENT SOURCE

DEPENDENT SOURCEIMPORTANT POINT TO DISCUSS

ELECTRICAL LOAD क्या है?
RESISTOR,INDUCTOR &
CAPACITOR

DEPENDENT SOURCEELECTRICAL LOAD
❖ Devices that are connected to the
power system are referred to as
electrical loads.
❖ Toasters, refrigerators, light bulb and
many more are considered electrical
loads.
❖ There are three types of electrical
loads, they vary according to their
leading or lagging time
relationship between voltage and
current.

DEPENDENT SOURCETYPES OF ELECTRICAL LOAD
LOAD
NATURE OF
LOAD
RESISTIVE
INDUCTIVE
CAPACITIVE
POWER SYSTEM
LOAD
INDUSTRIAL
DOMESTIC
AGRICULTURAL

RESISTOR
क्या है?
➢ DEFINITION
➢ TYPES OF RESISTOR
➢ COLOUR CODE
➢ PROPERTIES

RESISTOR DEFINITION
❖ A resistor is a passive two-terminal electrical component that implements
electrical resistance as a circuit element.
❖ In electronic circuits, resistors are used to reduce current flow, adjust
signal levels, to divide voltages, bias active elements, and terminate
transmission lines, among other uses.

DEPENDENT SOURCETYPES OF RESISTORS

DEPENDENT SOURCERESISTORS

DEPENDENT SOURCERESISTOR COLOUR CODE

RESISTOR
HEAT LOSS
I2RT
PASSIVE
ELEMENT
PROPERTY IS
RESISTANCE
SYMBOL
, R
STATIC
ELEMENT
LINEAR
ELEMENT
NO
HISTORY
LUMPED
ELEMENT
UNIT IS
OHM,
OBEY’S
OHMS
LAW
VOLTAGE
DROP
V=IR
PROPERTIES OF RESISTOR

DEPENDENT SOURCERESISTANCE
❖ Resistance is the property of resistor that offers some
obstruction to the current .
❖ Resistance is the 'opposition' to the current flow measured
in ohms ( Ω )

DEPENDENT SOURCERESISTANCE

WHAT IS
RESISTIVITY ?
ρ=E/J

DEPENDENT SOURCERESISTIVITY OF RESISTANCE
❖ Electric resistivity is defined as the electrical resistance offered per
unit length and unit cross-sectional area at a specific temperature and
is denoted by ρ.
❖ High resistivity designates poor conductors.
❖ Unit of resistivity is ohm-meter in MKS system and ohm-cm in CGS.
❖ Resistivity, commonly symbolized by the Greek letter rho, ρ.
ρ=E/J
ρ is the resistivity of the material in Ω.m
E is the electric field in V.m-1
J is the current density in A.m-2
Where,

DEPENDENT SOURCERESISTIVITY vs RESISTANCE

DEPENDENT SOURCEPROPERTIES OF RESISTANCE
❖ The resistance R is definitely directly proportional to the length of the
conductor.
So, Resistance (R) ∝ L …….length of conductor (l) ……..Eqn (i)
❖ The resistance R is certainly inversely proportional to the area of cross-
section of a particular conductor.
Resistance (R) ∝ 1/A …….cross section of the conductor (A)…… Eqn (ii)
Resistance (R) ∝ L/A
ρ = Resistivity of materialProf. Prasant Kumar BEEE 82

SERIES & PARALLEL
CONNECTION OF RESISTOR

DEPENDENT SOURCESERIES CONNECTION OF RESISTOR
❖ Resistors connected head-to-tail are in series.
❖ The equivalent overall resistance is the sum of the individual resistance
values.

PARALLEL CONNECTION OF RESISTOR

DEPENDENT SOURCESERIES & PARALLE CONNECTION OF RESISTOR

DEPENDENT SOURCEFIND EQUIVALENTVRESISTANCE

WHAT IS CAPACITOR
(संधाररत्र क्या है?)

DEPENDENT SOURCECAPACITOR
A capacitor is a device that stores electrical energy in an electric field.

DEPENDENT SOURCECAPACITOR
❖ The capacitor is a device in which electrical energy can be stored.
❖ It is an arrangement of two-conductor generally carrying charges
of equal magnitudes and opposite sign and separated by an insulating
medium.

DEPENDENT SOURCEWHAT ARE CAPACITORS USED FOR?
❖ Storing electric potential energy such as batteries.
❖ Filtering out unwanted frequency signals.
❖ Delaying voltage changes when coupled with resistors.
❖ Used as a sensing device.
❖ Used in the audio system of the vehicle.
❖ Used to separate AC and DC.
Application of Capacitor?

DEPENDENT SOURCEWHAT IS INSIDE THE CAPACITOR ?

DEPENDENT SOURCESYMBOL & UNIT OF CAPACITOR
❖ Unit of Capacitance: Farad (F)
Commonly Used Scales
•mF = 10-3F
•μF = 10-6F
•nF = 10-9F
•pF = 10-12

DEPENDENT SOURCECAPACITANCE OF CAPACITOR
❖ The charge on the capacitor (Q) is directly proportional to the
potential difference (V) between the plates.
The constant of proportionality (C) is termed as the capacitance of the
capacitor
Q α V
Q = CV

DEPENDENT SOURCEFACTORS AFFECTING THE CAPACITANCE
Capacitance depends on the following factor:
1.The area of the plates (A)
2.The distance between the plates (d)
3.The type of dielectric material
4.Temperature (T)

DEPENDENT SOURCEPROPERTIES OF CAPACITOR
CAPACITANCE (C) α Area of the two plates (A)
CAPACITANCE (C) α I/d (d=Distance b/w parallel plates)

DEPENDENT SOURCEHOW CAPACITOR WORK ?

CAPACITOR
STORE
P.E.=1/2
CV2
PASSIVE/AC
TIVE
ELEMENT
PROPERTY IS
CAPACITANCE
SYMBOL
, C
DYNAMIC
ELEMENT
LINEAR
ELEMENT
HAS
HISTORY/MEMORY
LUMPED
ELEMENT
UNIT IS
FARAD,F
PROPERTIES OF CAPACITOR

DEPENDENT SOURCESERIES CONNECTION OF CAPACITOR

DEPENDENT SOURCEPARALLEL CONNECTION OF CAPACITOR

Q α V
Q = CV

LEC#15
IN हहंINGLISH
WHAT IS INDUCTOR?
(प्रेरक या इंडक्टर क्या है?)

WHAT IS INDUCTOR?
❖ An inductor is a two-terminal
electrical component that
stores energy in a
magnetic field when electric
current flows through it.
❖प्रेरक या इंडक्टर (inductor) एक
वैद्युत अवयव है जिसमें कोई
ववद्युत धारा प्रवाहहत करने पर यह
चुम्बकीय क्षेत्र के रूप में उिाा का
भंडारण करता है।

DEPENDENT SOURCEWHAT IS INDUCTOR?

DEPENDENT SOURCEWHAT IS INDUCTANCE (प्रेरकत्ि )?
❖ Magnetic energy storage
capacity of inductor is called
Inductance
❖ Inductance (प्रेरकत्व) is the
tendency of an electrical
conductor to oppose a change
in the electric current flowing
through it.

DEPENDENT SOURCESYMBOL OF TYPES OF INDUCTOR
1.Iron Core Inductor
2.Air Core Inductor
3.Iron Powder Inductor
4.Ferrite Core Inductor
•Soft Ferrite
•Hard Ferrite
TYPES OF INDUCTOR

DEPENDENT SOURCEUNIT OF INDUCTOR INDUCTANCE?
UNIT OF INDUCTANCE IS HENRY (H)
ONE HENRY is the value of self-inductance in a coil in
which one volt is produced by a variation of the inducing
current of one ampere per second

DEPENDENT SOURCEIMPORTANT EQUATIONS OF INDUCTOR

DEPENDENT SOURCEFACTORS AFFECTING INDUCTANCE

INDUCTOR
STORE
K.E.=1/2
LI2
PASSIVE,
ACTIVE
ELEMENT
PROPERTY IS
INDUCTANCE
SYMBOL
, L
DYNAMIC
ELEMENT
LINEAR
ELEMENT
HAS
HISTORY/MEMORY
LUMPED
ELEMENT
UNIT IS
HENRY,H
PROPERTIES OF INDUCTOR

SERIES & PARALLEL
CONNECTION OF INDUCTORProf. Prasant Kumar BEEE 114

DEPENDENT SOURCESERIES PARALLEL CONNECTION OF INDUCTOR

DEPENDENT SOURCESERIES CONNECTION OF INDUCTOR

SERIES CONNECTION OF INDUCTOR

DEPENDENT SOURCEPARALLEL CONNECTION OF INDUCTOR

DEPENDENT SOURCESERIES -PARALLEL CONNECTION OF INDUCTOR

LEC#17
IN हहंINGLISH
OHM’S LAWProf. Prasant Kumar BEEE 121

DEPENDENT SOURCEOHM’S LAW
Georg Simon Ohm, a German
physicist was the first to verify Ohm’s
law experimentally in 1828.
Ohm’s law states the relationship
between electric current (I) and
potential difference (V).

DEPENDENT SOURCEOHM’S LAW STATEMENT
“The current flowing through a conductor between
two points is directly proportional to the voltage
across the two points, provided all physical
conditions and temperature, remain constant.
Flowing current Voltage

DEPENDENT SOURCEOHM’S LAW STATEMENT
Ohm’s Law Statement: Ohm’s law states that the voltage
across a conductor is directly proportional to the
current flowing through it, provided all physical
conditions and temperature, remain constant.
Voltage Flowing current

The vector form of Ohm's law used in electromagnetics
and material science:
J - Current density
E - Electric field
σ (sigma)=Conductivity.
This reformulation of Ohm's law is due to Gustav Kirchhoff

DEPENDENT SOURCEOHM’S LAW APPLICATIONS
❖To determine the voltage, resistance or current
of an electric circuit.
❖Ohm’s law is used to maintain the desired
voltage drop across the electronic
components.
❖Ohm’s law is also used in dc ammeter and
other dc shunts to divert the current.

DEPENDENT SOURCELIMITATIONS OF OHM’S LAW
❖Ohm’s law is not applicable for unilateral
electrical elements like diodes and transistors
as they allow the current to flow through in one
direction only.
❖Not applicable for non-linear electrical elements.
❖Not Applicable for non metals

DEPENDENT SOURCESHORT QUESTIONS ANSWERS ON OHM’S LAW
Q.What can Ohm’s Law be used for?
Ans:-Ohm’s law is used to validate the static
values of circuit components such as current
levels, voltage supplies, and voltage drops.

SHORT QUESTIONS ANSWERS ON OHM’S LAW
Q .Is Ohm’s Law Universal?
Ans:-No. Ohm’s law is not a universal law. This
is because ohm’s law is only applicable to
ohmic conductors such as iron and copper
but is not applicable to non-ohmic conductors
such as semiconductors.

DEPENDENT SOURCESHORT QUESTIONS ANSWERS ON OHM’S LAW
Q. Why is Ohm’s law not applicable to
semiconductors?
Ans:-Ohm’s law doesn’t apply to semiconducting
devices because they are nonlinear devices. This
means that the ratio of voltage to current doesn’t
remain constant for variations in voltage.

DEPENDENT SOURCE
Q. When does Ohm’s law fail?
Ans:-Ohm’s law fails to explain the behavior of
semiconductors and unilateral devices such as
diodes. Ohm’s law may not give the desired
results if the physical conditions such as
temperature or pressure are not kept constant.
SHORT QUESTIONS ANSWERS ON OHM’S LAW

BASIC ELECTRICAL ENGINEERING DC CIRCUITS UNIT 1 PART 1 NOTES

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