BASIC ELECTRICAL ENGINEERING DC CIRCUITS UNIT 1 PART 2 NOTES

BASICS OF ELECTRICAL ENGINEERING
PROPERTIES OF NETWORK
ELEMENTS LEC#18
IN हहंINGLISHककसी ने ये पढाया नह ं होगा
Prof. Prasant Kumar BEEE 134

L L P F B

LINEAR OR NON-LINEAR
ELEMENTS / NETWORK
अब भूल नह ं पाओगे
IN हहंINGLISH
LEC#19

❖ A circuit whose values does not changed with
respect to Current and Voltage is called Linear
Circuit.
LINEAR ELEMENTS

LINEAR ELEMENTS
❖ Linear Elements obeys the law of superposition
and homogeneity.

LINEAR ELEMENTS
❖ They obeys properties of ohm’s law
❖ These are elements in which the relation between
voltage and current is a linear function.

LINEAR ELEMENTS
Examples of linear elements are resistor, inductors
& capacitors

NONLINEAR ELEMENTS
❖ These are elements in which the relation
between voltage and current is a nonlinear
function.
❖ It does not obeys the law of superposition
and homogeneity.
❖ They does not obeys properties of ohm’s
law

An example is a diode, in which the current is an
exponential function of the voltage.
NONLINEAR ELEMENTS

LINEAR NETWORK/CIRCUIT
❖ Linear circuit in which circuit parameters
(Resistance, inductance, capacitance, etc) are
constant. In other words, a circuit whose
parameters are not changed with respect to
Current and Voltage is called Linear Circuit.

NONLINEAR NETWORK/CIRCUIT
❖ A circuit in which circuit parameters (Resistance,
inductance, capacitance, etc) are not constant.
In other words, a circuit whose parameters are
changed with respect to Current and Voltage is
called Linear Circuit.

सक्रिय क्रिष्क्रिय
IN हहंINGLISHअब भूल नह ं पाओगेLEC#20

WHAT IS ACTIVE सक्रिय ELEMENTS?
❖ An Electrical/Electronic component which supplies
energy to a circuit.
❖ Active elements have the ability to electrically
control electron flow (i.e. the flow of charge).

DEPENDENT SOURCEWHAT IS ACTIVE ELEMENTS?
❖ Voltage sources
➢ Battery, Generators (such as alternators and
DC generators)
❖ Current sources
➢ All different types of transistors (such as
bipolar junction transistors, MOSFETS, FETs)

WHAT IS ACTIVE ELEMENTS?
GENERATOR BATTERIES TRANSISTOR
PV CELL

WHAT IS PASSIVE ELEMENTS?
❖ A passive component is an Electrical/Electronic
component which can only receive energy,
which it can either dissipate, absorb or store it
in an electric field or a magnetic field.
❖Passive components cannot amplify, oscillate,
or generate an electrical signal.

❖ Common examples of passive components
include:
✓ Resistors
✓ Inductors
✓ Capacitors
✓ Transformers
WHAT IS PASSIVE ELEMENTS?

RESISTOR AS A PASSIVE ELEMENTS
It can not deliver any energy to a circuit. Instead
resistors can only receive energy which they can
dissipate as heat as long as current flows through it.

INDUCTOR AS A PASSIVE ELEMENTS?
❖ It is a passive element of circuit, because it can
store energy in it as a magnetic field.
❖ Although it can deliver that energy to the circuit,
but not in continuous basis.
❖ The energy absorbing and delivering capacity of
an inductor is limited and transient in nature.

CAPACITOR AS A PASSIVE ELEMENTS
❖ A capacitor is considered as a passive element
because it can store energy in it as electric field.
❖ The energy dealing capacity of a capacitor is
limited and transient.
❖ It is not actually supplying energy, it is storing it
for later use.

INDUCTOR & CAPACITOR

IN हहंINGLISH
LEC#21 अब भूल नह ं पाओगे
R L C
UNILATERAL OR BILATERAL?

WHAT IS BILATERAL ELEMENTS?
Conduction of current in both directions in a circuit
element with same magnitude is termed as a
bilateral circuit element.

WHAT IS BILATERAL ELEMENTS?
Examples: Resistor,Inductor capacitor etc.

WHAT IS UNILATERAL ELEMENTS?
❖ The unilateral circuit element does not offer same
resistance to the current of either direction.
❖ The resistance of the unilateral circuit element is
different for forward current than that of reverse
current.

WHAT IS UNILATERAL ELEMENTS?
Examples: Diode, transistor etc.

अब भूल नह ं पाओगे
LEC#22
IN हहंINGLISH

WHAT IS LUMPED ELEMENTS?
In lumped elements electrical parameters (R, L, C)
are assumed to be concentrated at one place.
Example: Resistor connected in any electrical circuit.
LUMPED

WHAT IS DISTRIBUTED ELEMENTS?
When the voltage across and current through the
element change with dimensions of the element.
Example: Resistance of a long transmission line.
❖ It varies with the length of the line.

LUMPED VS DISTRIBUTED ELEMENTS

LEC#23
IN हहंINGLISH
9 ममनट में 4 सिाल

A two terminal component that connected to an
electric circuit is an element.

❖ Branch is the portion of the circuit between two
nodes which can deliver or absorb energy.
❖ As per this definition, the short circuit between two
nodes is not referred as branch of electric circuitProf. Prasant Kumar BEEE 167

❖ A point where network element is connected
to the circuit is called node.

❖ For two different nodes, their voltages must be
different.

❖ If there is no element between two or more connected
adjacent nodes, these nodes can be recombined as a
single node

A point where three or more branches meet
together is called a junction.

NODE VS JUNCTION
❖ Every junction is a node but every node may
or may not be a junction.
Nodes:
Points (ab),c,(de) & f.
Junction:
C & f are called
junction.

LEC#24
IN हहंINGLISH

❖ In 1845, a German physicist,
Gustav Kirchhoff developed
a pair or set of rules or laws
which deal with the
conservation of current
and energy within electrical
circuits.

KIRCHHOFF’S
LAW
KIRCHHOFF’S
CURRENT
LAW
KIRCHHOFF’S
VOLTAGE
LAW

The algebraic sum of currents at a
node/junction is zero.
STATEMENT:-
Incoming Current
Outgoing Current

The incoming current is equal to outgoing
current at a node.

The sum of current entering a node is equal to
sum of currents leaving that node

❖ Kirchhoff’s Current law is based on Conservation
of Charge.

LEC#25
IN हहंINGLISH

❖ In 1845, a German
physicist, Gustav Kirchhoff
developed a laws which
deal with the conservation
of energy within electrical
circuits.

STATEMENT:- For any closed path in a network,
the algebraic sum of the voltages is
zero

The algebraic sum of all emf or voltage in a loop
is equal to the algebraic sum of product of
current and resistance of various branches in that
loop.

Kirchhoff’s voltage law is based on Conservation of
Energy.

LEC#26
IN हहंINGLISH

A mesh is a loop that has no other circuit paths
inside it.
In other words, a loop with no other loops inside it.

A loop is a closed path in a circuit where two nodes
are not traversed twice except the initial point, But
in a loop other paths can be included inside.

Q. A mesh is a loop which contains ____ number of
loops within it.
a) 1
b) 2
c) 3
d) No loop

Q. Consider the circuit shown below. The number meshes
and loops are?
a) 2,2
b) 2,3
c) 3,2
d) 2,4

LEC#27
IN हहंINGLISH

❖ Mesh Current Analysis is a technique used to find
circulating currents around a loop or mesh with
in any closed path of a circuit.
❖ Kirchhoff’s Voltage Law (KVL) used to
determine mesh current in Mesh Analysis.

Steps For Mesh Analysis
Q. Find currents using mesh analysis.

Step 1- Find number of meshes in given circuit.

Step 2- Assume mesh current in each mesh CW
or ACW.
.

Step 3-Apply KVL to write equations
No of KVL equations in circuit are

Step 4- Solve all equations and find branch currents

Solve all equations and find branch currents

Q. Find currents using mesh analysis.

LEC#28
IN हहंINGLISH

❖ Nodal analysis, node-voltage analysis, or the
branch current method is a method of
determining the voltage (potential difference)
between "nodes".
❖ Nodal Analysis is based on Kirchhoff's Current
Law (KCL).

Steps For Nodal Analysis
Q. Find nodal voltages using node analysis.

Step 1- Find number of nodes in given circuit.

Step 2- Assign node voltages in given circuit.

Step 3- Write nodal equations using KCL.
No. of nodal equations:-

Step 4- Write nodal equations

Step 4- Solve all equations and find node voltages.

Q. Find nodal voltages using node analysis.

SUPERMESH &
SUPERNODE क्या है?
IN हहंINGLISH
LEC#29

A supermesh forms when two meshes have a
common current source (dependent or
independent).

A supermesh is a larger loop which has both meshes
inside.

In a circuit when only voltage source
(dependent or independent) is connected
between two nodes is called SUPERNODE.

In a circuit when ideal voltage source appears
between two nodes is called SUPERNODE.

At what condition a network mesh and node become
supermesh & supernode?

SUPERMESH
ANALYSIS क्या है?
IN हहंINGLISH
LEC#30

SUPERMESH analysis is special case of mesh analysis

MESH ANALYSIS
=
KVL+OHM’S LAW
SUPERMESH ANALYSIS
=
KVL+OHM’S LAW+KCL

Q. Find currents using mesh analysis

SUPERNODE
ANALYSIS क्या है?
IN हहंINGLISH
LEC#31

In a circuit when only voltage source (dependent or
independent) is connected between two nodes is
called SUPERNODE.

NODAL ANALYSIS
=
KCL+OHM’S LAW
SUPERNODE ANALYSIS
=
KCL+OHM’S LAW+KVL

Q. Find out node voltages using nodal analysis ?

Incoming Current
Outgoing CurrentProf. Prasant Kumar BEEE 242

Q. Find out node voltages using nodal analysis ?

का उपयोग
और प्रकार
IN हहंINGLISH LEC#32Prof. Prasant Kumar BEEE 245

Electric circuit theorems are always beneficial to
help find voltage and currents in multi-loop circuits.

NETWORK
THEOREMS
TELLEGEN’S
THEOREM
COMPENSATION
THEOREM
SUBSTITUION’S
THEOREM
SUPERPOSITION
THEOREM
THEVENIN’S
THEOREM
NORTORN’S
THEOREMS
MAXIMUM POWER
TRANSFER
THEOREM
MILLIMAN’S
THEOREM
RECIPROCITY
THEOREM

DC CIRCUITS
IN हहंINGLISH

Statement (DC circuit) A linear active network consisting of a
number of voltage sources and resistances can be replaced by
an equivalent network consisting voltage source called
Thevenin’s voltage (Vth) and a series connected resistance
called Thevenin’s resistance (Rth).

Thevenin’s voltage
Thevenin’s resistance
Load resistance
Load Current

Statement (AC circuit) Any combination of sinusoidal AC
sources and impedances with two terminals can be
replaced by a single voltage source (Eth) and a single
series impedance zth.

Thevenin’s open circuit
emf/voltage
Thevenin’s equivalent
impedance
Load resistance
Load current

Procedure:
-
Q . Develop Thevenin's equivalent circuit of given network
and find load current across load resistance RL.

Procedure:
STEP-1:-Remove Load resistance (RL)

STEP-2:-Calculate Thevenin's equivalent resistance (Rth)
Deactivate all independent active sources and consider
their internal resistance.
Voltage Source- Short circuit (R=0 )
Current Source- Open circuit (R= )

STEP-3:-Calculate Thevenin's equivalent voltage (Vth)

STEP-4:-Develop Thevenin's equivalent circuit & find I

IN हहंINGLISHLEC#34

Q .Develop Thevenin’s equivalent circuit of given network
and find load current across load resistance R =3

STEP-1:-Remove Load resistance (RL)

STEP-2:-Calculate Thevenin's equivalent resistance (Rth)

STEP-3:-Calculate Thevenin's equivalent voltage (Vth)

STEP-4:-Develop Thevenin's equivalent circuit & find I

Q .Develop Thevenin's equivalent circuit of given network
and find load current across load resistance RL= .

LEC#35
IN हहंINGLISH

It states that in any linear, active, bilateral network having
more than one source, “The overall response in any branch
of a network is equal to algebraic sum of all the responses of
each individual source.”

Procedure:
STEP-1:-Let us assume current (responses) when
all sources are active.

STEP-2:-Consider only one active source at a time and
deactivate all other sources and consider their internal
resistance.
Current Source- Open circuit (R= )
Consider single active voltage source (V1) & deactivate (SC)
other voltage V2.Assume currents in each branch.

STEP-2:-Consider another single active voltage source &
deactivate (SC) other voltage V1.
Assume currents in each branch.

STEP-3:-Apply superposition theorem statement

LEC#36
IN हहंINGLISH

Q .Find out branch currents using superposition theorem.

STEP-1:-Let us assume current (responses) when all sources
are active.

STEP-2:- Consider single active current source ( ) &
deactivate (SC) voltage V2.Assume currents in each branch.

STEP-3:- Consider voltage source ( ) & deactivate current
source by open circuit. Assume currents in each branch.

STEP-3:-Apply superposition theorem statement

Solve same numerical using mesh analysis and verify
superposition theorem.

Q .Find out branch currents using superposition theorem.

STAR DELTA ANALYSIS
STAR-DELTA CONVERSION
LEC#37

Q.WHAT IS STAR CONNECTION?
Q.WHAT IS DELTA CONNECTION?
Q.WHY STAR CONNECTION IS CALLED Y & T CONNECTION?
Q.WHAT IS COMMON POINT OR NEUTRAL POINT?
Q.HOW WE CONVERT STAR NETWORK INTO DELTA NETWORK?
Q.HOW WE CONVERT DELTA TO STAR?

The terminals of the three branches are connected to
a common point. The network formed is known
as Star Connection.
The common point is known as the neutral point.

Y -CONNECTION T -CONNECTION

The three branches of the network are connected in
such a way that it forms a closed loop known as
Delta Connection.
The common point/neutral point is not avaliable.

LEC#38
वोल्टेि स्रोत को
CURRENT स्रोत
में बदलें VICE VERSA

Source transformation is the process of simplifying a
circuit solution, especially with mixed sources, by
transforming voltage sources into current
sources, and vice versa.
VOLTAGE
SOURCE
CURRENT
SOURCE

PRACTICAL CURRENT
SOURCE
PRACTICAL VOLTAGE
SOURCEProf. Prasant Kumar BEEE 298

PRACTICAL CURRENT
SOURCE
PRACTICAL VOLTAGE
SOURCEProf. Prasant Kumar BEEE 300

CURRENT &
VOLTAGE
DIVISION
RULE
WITH
NUMERICAL
LEC#39

Voltages are different in series connected resistors/elements.
Current is same in series connected resistors/elements.
Current is divided in parallelly connected resistors/elements
Voltage is same in parallel connected resistors/elements.

The voltage is divided between two resistors which
are connected in series in direct proportion to
their resistance.

WITH
NUMERICAL
NUMERICALS ON
EQUIVALENT RESISTANCE
LEC#40
FIND
RAB ?
FIND
I ?

Q. Find RAB IN THE CIRCUIT

Q. Determine the current supplied by the source in the circuit shown
below.

322Prof. Prasant Kumar BEEE
THANKS TO ALL
FOR ANY PROBLEN,FEEL FREE TO VISIT YOUTUBE
FOR DETAIL UNDERSTANDING @.

BASIC ELECTRICAL ENGINEERING DC CIRCUITS UNIT 1 PART 2 NOTES

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BASIC ELECTRICAL ENGINEERING DC CIRCUITS UNIT 1 PART 2 NOTES