Basic electronics according to ktu syllabus

1. Viji R
Assistant Prof in ECE
GEC Idukki
Nov 2022

2. Resistors, Capacitors and Inductors
Types, specifications. Standard values, color
coding.

5.  Resistors, Capacitors, Inductors, Transformers,
Relays,Transistors, diodes etc.
 Two types of electronic components
 Passive components
 Active components
 The electronic components which are not
capable of amplifying or processing an electrical
signal are called passive components
 The electronic components which are capable of
amplifying or processing an electrical signal are
called active components

6.  Resistors
 Capacitors
 Inductors
 Relays

7.  Tube devices
 Vacuum tubes
 Gas tubes
 Semiconductor devices
▪ Bipolar Junction Transistor (BJT), Junction Field Effect
Transistors (JFET), Diodes, Silicon Controlled Rectifiers
(SCR) etc.

8.  Diodes
 BJTs
 JFTs
 Digital ICs
 Analog ICs

10.  A Resistor works on the principle of Ohm’s
law and the law states that the voltage across
the terminals of a resistor is directly
proportional to the current flowing through it
 “Resist” , regulate or set the flow of electrons
(current) by using the type of conductive
material from which they are composed

11.  Resistance is a fundamental property of conductor
to oppose the flow of current through it
cm
ohm
in
material
conductor
the
of
y
resistivit
cm
in
conductor
the
of
area
tional
Cross
A
cm
in
conductor
the
of
length
l





2
sec
A
l
R



12.  Standard Resistor Symbols
 Value of its resistance given in Ohms, Ω.
 Fixed or variable
 volume control, brightness and contrast
control ofTV etc –uses of variable resistor

16. 00 is the nominal value.
4 
7
Violet = 7
Red = 2
Gold = 5%
5% of 4700 = 235
4700 + 235 = 4935
4700 - 235 = 4465
The actual value can range from 4465 to 4935 .
00 is the nominal value.
4 
700 is the nominal value.
4 
00 is the nominal value.
00 is the nominal value.
4 
7
Violet = 7
Red = 2
Gold = 5%
5% of 4700 = 235
4700 + 235 = 4935
4700 - 235 = 4465
Violet = 7
Red = 2
Gold = 5%
5% of 4700 = 235
4700 + 235 = 4935
4700 - 235 = 4465
The actual value can range from 4465 to 4935 .
Yellow = 4

17. 1 k (950 to 1050 )
390  (370.5 to 409.5 )
22 k (20.9 to 23.1 k)
1 M (950 k to 1.05 M)

22.  Resistance / Ohmic value
 Tolerance
 Wattage rating / Power rating
 Temperature coefficient of resistance (TCR)
 Voltage coefficient of resistance (VCR)
 Voltage rating
 Noise
 Stability
 Reliability

23.  Resistance/ Ohmic value
 10Ω, 4.7K Ω, 1M Ω (Ω, K Ω, or M Ω)
 Tolerance
 It is the percentage deviation from the rated value
 Wattage rating / Power rating
 It is the maximum power in watts that the resistor
can safely dissipate.
 Physical size of a resistor gives an indication of its
wattage rating

24.  Temperature coefficient of resistance (TCR) (α )
 Resistance of materials changes with temperature
▪ Metals & alloys (increase in R)
▪ Carbon & Graphite (decrease in R)
 It is quite important to take the effect of
temperature while designing a circuit
 A quantity which describes how much variation
occurs in resistance with temperature
 α is often described in ppm/°C (ppm - parts per
million)
 Mathematical expression  
 
2
1
2
1 1 T
T
R
R T
T 

 

25.  Assume a resistor of 50 ohm with TCR 20ppm/°C
is in a product that heats up from room
temperature(25°C) to 50°C. Find resistor’s
maximum) change caused by that rise in
temperatue.
 50 (the resistor value) x 0.000020 (TCR) x 25 (the
temp change). That is, the resistor's value would
change no more than 0.025 ohms.
𝑅2 = 𝑅1 1 + 𝛼 𝑇2 − 𝑇1
𝑅2 − 𝑅1 = 𝑅1 𝛼 𝑇2 − 𝑇1

26.  Voltage Coefficient of Resistance (VCR)
 It can be defined as the change in resistance with
respect to the voltage applied over a specific
voltage range
 Expressed in ppm/V
 A resistor with aVCR of 100 ppm/V will change 0.1
% over a 10V change and 1 % over a 100V change.
6
2
1
2
2
1
10
1
V
V
R
R
R
t
coefficien
Voltage




27.  Voltage rating
 Maximum voltage that can be applied across the resistor
 Noise
 When current passes through a resistor it produces a thermal agitation.This
agitation creates disturbances called noise.
 Thermal noise or Johnson noise
 Measured in micro volts
 Stability
 The change in resistance value under specific physical and electrical operating
conditions (%).
 Reliability
 Normally the resistor should not undergo any change in value except a small
percentage after a long use.
 Reliability is a factor, which gives the percentage of failure per 1000 hours of
use.
PxR
V 
max

28.  Stability
 The change in resistance value under specific physical
and electrical operating conditions (%).
 Reliability
 Normally the resistor should not undergo any change
in value except a small percentage after a long use.
 Reliability is a factor, which gives the percentage of
failure per 1000 hours of use.

29.  Carbon Composition Resistor
 Carbon/metal/cermet film resistor
 Wire wound resistor
 Surface Mount resistor

30.  General purpose type
 Wire-wound type
 Carbon type
 Precision type
 Wire-wound type
 Commonly used
 Potentiometers (Pot)
 Rheostat
 Preset

31.  Their resistive element is manufactured from a mixture of
finely ground carbon dust or graphite (similar to pencil lead)
and a non-conducting ceramic (clay) powder to bind it all
together.
 The ratio of carbon dust to ceramic (conductor to insulator)
determines the overall resistive value of the mixture and the
higher the ratio of carbon, the lower the overall resistance.
 The mixture is moulded into a cylindrical shape with metal
wires or leads are attached to each end to provide the
electrical connection, before being coated with an outer
insulating material and colour coded markings to denote its
resistive value.

32. 1Ω – 22MΩ

33.  Advantages
 Small in size
 Cheap & reliable
 High stability
 High voltage withstand capacity
 Nil inductance
 Low capacitance
 Disadvantages
 Highly sensitive to temperature variation
 Not suitable for high precision application (High tolerance
range 5% - 20%)
 Low power dissipation capacity : 0.1 to 2W
 Noise is high (due to the mixture of different materials)
 The noise level increases when current flows through it

34.  Applications
 High voltage power supply
 Welding controls
 High frequency application
 General purpose electronic equipments
 Typical specifications
 Resistance range – 2.7 Ω to 22M Ω
 Tolerance - ±5% to ±20%
 Operating temperature - -55^oC to 100^oC
 Power rating – 1/8W to 2W
 DC working voltage – 150V to 500V

35.  The generic term “Film Resistor” consist of Metal
Film, Carbon Film and Metal Oxide Film resistor types, which
are generally made by depositing pure carbon ,pure metals,
such as nickel, or an oxide film, such as tin-oxide, onto an
insulating ceramic rod or substrate.
 The resistive value of the resistor is controlled by increasing
the desired thickness of the deposited film giving them the
names of either “thick-film resistors” or “thin-film resistors”.
 Once deposited, a laser is used to cut a high precision spiral
helix groove type pattern into this film. The cutting of the
film has the effect of increasing the conductive or resistive
path, a bit like taking a long length of straight wire and
forming it into a coil.

36.  The cutting of grooves is stopped when the
desired resistance value is achieved
 Contact caps are fitted on both ends
 The lead wires, made up of tinned copper, are
then welded to these end caps.
 The resistance is then enclosed in a plastic
jacket (phenolic resin) or coated with epoxy.
 Colour coding

37.  Allows for much closer tolerance resistors
(1% or less) as compared to the simpler
carbon composition types.
 Achieve a much higher maximum ohmic
value compared to other types and values in
excess of 10MΩ are available.
 Better temperature stability .

38.  Carbon film resistors
 Metal film resistors
 Metal oxide film resistors
 Cermet film resistor

40.  Advantages (carbon film)
 Low noise
 Low temperature coefficient
 Because of the use of pure carbon, it has high
negative temperature coefficient than carbon
composition
 Good high frequency response
 Good stability

41.  Applications
 Professional measuring and calibrating
equipments
▪ Oscilloscope
▪ Digital multimeters
▪ High frequency communication systems
 High voltage power supplies
 Radar
 X-rays
 Laser

42.  Material :
Metal alloys Nichrome (Nickel and Chromium)
 The stability, temperature coefficient and tolerance are
better than that of carbon film.
 Typical tolerances are between 0.5% and 2%
 Temperature coefficient between 50 and 100 ppm/K.
 Stability is lower than that of wire-wound resistor
 High frequency properties are better than wire-wound

43.  Cermet resistors are a type of film resistor for
which a thicker conducting paste is used.
 The paste is a mix of both ceramic and metal, thus
the term “cermet.” A cermet can combine
attractive properties of both a ceramic, such as
high temperature resistance and hardness, and
those of a metal, such as the ability to undergo
plastic deformation
 Cermet resistors possess qualities of low noise,
good temperature stability, and decent voltage
ratings.

44.  Constructed from a long fine wire(usually alloys like
nickel-chromium or copper-nickel-manganese )
wound on a core (ceramic , plastic or glass)
 The length of the wire used and its resistivity
determine the resistance .
 The wounded wire is covered with an insulating
material such as vitreous enamel, which opposes or
blocks the outside heat.

45.  Available in power ratings from 5W to several
hundred watts and resistance values from 1Ω
to 100 k Ω
 Either fixed value or variable type.
 Wire wound resistors are used where:
1.Large power dissipation is necessary
2. Precise and stable resistance values are
required as for meter shunts and multipliers
3.Low frequency applications

47.  Advantages
 High precision
 Less sensitive to ambient temperature variations
 High power handling capacity
 Disadvantages
 Inductive and capacitive effect
 These influence the current flow in an alternating
current circuit
 Not suitable for high frequency application
 Large size

49.  Surface mount resistors( SMD resistors ) use surface mount
technology, SMT to provide considerable advantages in terms of
space saving and automated manufacture of printed circuit
boards.
 Most consumer and professional / industrial electronics is now
manufactured using surface mount technology.
 SMD resistors are rectangular in shape
and as a result they are often known
as chip resistors.
 They have metallised areas at either
end of the main ceramic body, and in
this way they can be set onto a printed
circuit board that has pads onto which
the two ends are set to provide the
connection.

50.  SMD resistors are rectangular in shape and as a
result they are often known as chip resistors.
 They have metallised areas at either end of the
main ceramic body, and in this way they can be set
onto a printed circuit board that has pads onto
which the two ends are set to provide the
connection.

51.  The resistor is made by taking an alumina or
ceramic substrate.
 Then a thin film of resistive material is
deposited - this is typically metal oxide or a
metal film. The length, thickness and material
used all determine the resistance of the
component.
 Once the resistive element has been
completed it is covered with successive
layers of a protective coating to prevent
mechanical damage and to prevent ingress of
moisture and other contaminants.
 The final stage is to apply a marking

52. https://www.electronics-notes.com/articles/electronic_components/resistors/surface-mount-smt-smd-resistor.php
Surface mount technology enables the components to be placed onto the printed circuit board and
then directly soldered to it. This eliminates the need for leads to connect the component body to the
board and it also means that leads do not have to pass through the board which always presented
significant issues for automated manufacture.

53. • Size: Surface mount resistors are naturally much
smaller in size , therefore they enable greater levels of
achieved.
• Reduced inductance: They have much lower levels of
stray inductance and capacitance and as a result they
much higher frequency operation.
• Accuracy and tolerance: High tolerance, good
temperature coefficient of resistance and long term
• Power rating: The power rating of SMT resistors is
smaller than that of traditional axial leaded
• Rework: When rework is required more difficulty
compared to using leaded components.

54.  Linear type
 The former (the part over which the wire is wound)
is of uniform height.
 Hence, the resistance varies linearly with the
rotation of the contact.
 Non-linear (tapered) type
 The height of the former is non-uniform.
 A tapered strip is taken as the former.
 Uniform pitch is ensured.

55. Wiping contact
Fixed contact
Rheostats are two-terminal devices.
Wiper arm
Wiping contact
Fixed contact
Rheostats are two-terminal devices.
Wiper arm

58. • When a resistor’s power rating is exceeded, it can
burn open or drift way out of tolerance.

60.  Capacitor is a device that can store electrical
charge on their plates when connected to a
voltage source

61.  Ceramic capacitor
 Plastic film capacitor
 Paper capacitor
 Mica capacitor
 Electrolytic capacitor
 Super capacitor

62.  Most widely used
 Mainly used where small physical size and
large charge storage is required

63.  Ceramic material is chosen
as dielectric because of its
great ability to allow
electrostatic attraction
and repulsion.
 Also, ceramic materials
are poor conductors of
electricity

64.  Ceramic disc capacitor
 Ceramic tubular capacitor
 Multilayer ceramic capacitor (MLCC)

66.  Made by coating silver on both sides of the
ceramic disc.
 The ceramic disc acts as the dielectric and metals
(silver, copper etc)coated on both sides of the
disc acts as electrodes.
 The tinned wire leads are attached to the ceramic
disc by using soldering technique.
 A protective coating is applied to the ceramic disc
capacitor to protect it from heat.
 For low capacitance, a single ceramic disc coated
with silver is used whereas for high capacitance
multiple layers are used.

67.  The area of a ceramic disc or dielectric and
spacing between the silver electrodes also
determines the capacitance of the ceramic
disc capacitor.
 The main disadvantage of using ceramic disc
capacitor is its high capacitance change with
slight change in temperature.

68.  Ceramic tubular capacitor is a hollow
cylindrical ceramic material.
 The inner and outer surfaces of the hollow
cylindrical ceramic material are coated with
the silver ink.
 The hollow cylindrical ceramic material acts
as the dielectric and the silver ink coated on
inner and outer surfaces acts as electrodes.

70.  Multiple layers of ceramic
material and conductive
electrodes placed one above the
other.
 The conductive electrodes are
placed between each layer of
ceramic material.
 The total capacitance of MLCC is
obtained by multiplying the
capacitance of one layer by total
number of layers.

71. Applications of ceramic capacitors
The various applications of ceramic capacitors include:
 Automatic volume control filtering
 Antenna coupling
 Resonant circuit
 Volume control RF bypass
 Lighting ballasts
Advantages of ceramic capacitor
 High stability
 Low losses
 High capacitance
 Small size

72.  Plastic film ( polyester, polypropylene,
polyethylene terephthalate, and
polyphenylene sulfide )is used to construct
the dielectric and aluminum or zinc is used to
construct the electrodes of the capacitor
 Mainly used in circuits where low loss and
high insulation resistance is required

73.  Film-foil capacitors
 Metallized film capacitors

74.  The film-foil capacitor is
made of two plastic films
or sheets; each is layered
with thin aluminum metal
foil or sheet.
 The plastic sheets and
aluminum sheets are then
rolled in the form of a
cylinder and wire leads are
attached to the both ends
of aluminum sheets.

76.  In metallized film capacitors, the aluminum
sheet or foil is replaced by a thin layer of
metal (Al or Zn) vacuum deposited on the film
layer.

77.  The major advantage of film dielectric
capacitors over natural dielectric capacitors is
that the plastic film is synthetic or artificial.
Therefore, we can able to increase thickness and
heat resistance of the dielectric. In other words,
we can change the thickness and heat resistance
of the plastic film capacitor.
 OtherAdvantages of film capacitors
 High stability
 Low cost
 Low losses even at high frequencies

78.  Paper capacitor uses paper as the dielectric to
store electric charge.
 It consists of aluminum sheets and paper
sheets.
 The paper sheet is covered or soaked with oil
or wax to protect it from outside harmful
environment

80.  The paper sheet capacitor is made by taking two
or more aluminum sheets and placing a paper
sheet between them
 The paper sheets and aluminum sheets are
rolled in the form of cylinder and wire leads are
attached to both ends of the aluminum sheets.
 The entire cylinder is then coated with wax or
plastic resin to protect it from moisture in the air.
 The paper sheet capacitors are used in the high
voltage and high current applications.

81.  In metalized paper capacitor, the paper is
coated with thin layer of zinc or aluminum.
The paper coated with zinc or aluminum is
rolled in the form of cylinder.The entire
cylinder is then coated with wax or plastic
resin to protect it from moisture.

83.  The main disadvantage of using paper
capacitor is that it easily absorbs moisture
(water vapor) from the air which decreases
the insulation resistance of the dielectric.
 The paper sheet capacitors are used in the
high voltage and high current applications.

84.  Mica is a silicate mineral found in granites and
other rocks
 In mica capacitors, mica is used as dielectric
material (Muscovite or white mica, ruby or
rose mica and amber mica)
 Two types
 Stacked mica
 Silvered mica

85.  The stacked mica capacitors are made of thin
mica sheets arranged one over another and
each mica sheet would be separated by thin
metal sheets of copper or aluminum.
 The entire unit is enclosed in a plastic case to
protect it from mechanical damage and
moisture.
 Terminals are connected at each end of the
mica capacitor.

86.  Silvered mica capacitors are made by coating
either side of the mica sheets with silver by
using screening technique.
 Several silver-coated mica sheets are
arranged one over other to achieve the
desired capacitance
 .The silver coated on the mica acts as
electrodes and mica sheets acts as dielectric.

89. Advantages of mica capacitors
 Stable capacitance
 Operates at high
temperatures
 Withstand at very high
voltages
 Low losses
 Highly accurate
 Dielectric provides good
insulation
Disadvantages of mica
capacitors
 High cost
 Proper sealing is required
Applications of mica
capacitors
•Ideal for HF and RF
•Coupling circuits
•Resonance circuits
•RADAR
•LASER
•Space
•Filters

90.  Electrolytic capacitors are mainly used when
high charge storage in a small volume is
required.
 In electrolytic capacitors, the liquid
electrolyte acts as one of the electrodes
(mostly act as cathode).
 Aluminum electrolytic capacitors
 Tantalum electrolytic capacitors
 Niobium electrolytic capacitors

91.  Aluminum electrolytic capacitor is made of
two aluminum foils, aluminum oxide layer, an
electrolytic paper or paper spacer soaked in
electrolytic liquid or solutions and liquid or
solid electrolyte.
 Electrolytic liquid contains atoms or
molecules that have lost or gained electrons.

94.  In aluminum electrolytic capacitor, the anode (+) and
cathode (-) are constructed using pure aluminum foil.
 The anode aluminum foil is coated with a thin layer of
insulating aluminum
 This insulating aluminum foil acts as dielectric of the
electrolytic capacitor
 The cathode and oxide coated anode is separated by
an electrolytic paper (which is soaked in an electrolytic
liquid).
 The cathode aluminum foil also covered with very thin
insulating oxide layer or dielectric naturally formed by
air.

95.  A plus or minus sign is written near any one of
the lines to represent whether it is positive or
negative terminal (anode or cathode)

96. Advantages of electrolytic capacitors
 Large amount of charge storage is achieved
 Low cost
Disadvantages of electrolytic capacitors
 Large leakage current
 Short lifetime
Applications of electrolytic capacitors
 The various applications of electrolytic
capacitors include:
 Filters
 Time constant circuits

97.  Nominal Capacitance( C )
 WorkingVoltage
 Tolerance
 Leakage Current
 WorkingTemperature
 Temperature Coefficient
 Polarization (mainly electrolytic)
 Equivalent Series Resistance, ( ESR )
 ESR, of a capacitor is the AC impedance of the capacitor
when used at high frequencies and includes the resistance
of the dielectric material, the DC resistance of the
terminal leads, the DC resistance of the connections to
the dielectric and the capacitor plate resistance all
measured at a particular frequency and temperature.

99. Metalised Polyester Capacitor
Disc & Ceramic Capacitor

101. Capacitor Voltage Reference
•Type J – Dipped Tantalum
•Type K – Mica
•Type L – Polyester/Polystyrene
•Type M – Electrolytic 4 Band
•Type N – Electrolytic 3 Band

103.  Inductor is a coil wound on a suitable material
 Inductor opposes sudden changes in the flow
of current in a circuit

104.  When current flows through a coil, it generates a
magnetic field.
 This magnetic field reacts so as to oppose any
change in the current.
 The reaction of the magnetic field, trying to
keep the current flow at a steady rate is known
as inductance .
 Inductance is measured in Henry (H)
 An inductor offers high impedance to ac
and low impedance to dc

105. l
A
N
L
2


coil
the
of
length
section
cross
of
Area
A
coil
the
of
turns
of
Number
N
medium
the
of
ty
permeabili




l


107.  Inductance
 Current rating
 Frequency range
 Loss factor
 Losses across the winding resistance of the coil
 Reciprocal of quality factor
 Inductive reactance
 Quality factor (Q)
 DC resistance
 Saturation current
 Self resonant frequency
fL
j
L
j
XL 
 2



108.  Saturation current
 The current at which the level of inductance falls by a specified amount
▪ In an inductor it is possible to saturate the core because there is a limit to the level of magnetic flux a
magnetic core can take.When this occurs the relative permeability falls and in turn this causes the level
of inductance to falls
 Self resonant frequency
 In view of the self-capacitance or distributed capacitance, the inductor forms a parallel
resonant circuit
 When inductor resonates the inductive reactance and the capacitive reactance will cancel
each other, and the overall impedance of the circuit will fall to a value governed by the DC
resistance of the circuit.
 Below the resonant frequency the inductive reactance will dominate
 Above the self-resonant frequency the capacitive reactance will dominate
 Inductors are normally used below their self-resonant frequency to ensure that the effects of
self-resonance are not experienced
 Quality factor (Q)
cycle
per
dissipated
Energy
cycle
per
stored
energy
Maximum
Q

2

R
X
R
L
Q L




109.  Inductors are used
 Energy storage elements
 Filter circuits
 Tuning circuits
 Oscillators
 Power supplies
 Inductive sensors (force, vibration, displacement etc.)
 Transformers
 Auto transformers

110.  Fixed Inductors
 Various types of cores
▪ Air
▪ Ferrite
▪ Powdered iron
▪ Laminated iron
 Variable Inductors
 By varying the core
reluctance

111.  Filter choke
 AF choke
 RF choke

113.  Coils wound on plastic, ceramic, or other
nonmagnetic forms, as well as those that have
only air inside the windings
 Lower inductance value
 Can be used at high frequencies
 Because they are free from energy losses called core
losses
 Due to lack of support for the coil the inductance value
can be changed during mechanical vibration
 Highly stable
 Low core losses
 High Quality factor

114.  Used for high power and high inductance
types of inductors
 Used in audio coils or chokes
 Audio equipments

115.  Ferrite is one of the most widely used cores
 Ferrite is a metal oxide ceramic based around
a mixture of Ferric Oxide, Fe2O3 and either
manganese-zinc or nickel-zinc oxides which
are extruded or pressed into the required
shape
 inductance is very high with ferrite core

116.  Formed from very fine particles with
insulated particles of highly pure iron powder
 This provides high permeability, thereby
enabling much higher inductance coils
 Inductors can be manufactured in small size.
 Switching power supplies.

117.  Rectify ac to dc
 Many turns of fine wire wound on an iron core
made of laminated sheets of E and I shapes
 1 H to 50 H , current upto 500 mA

118.  AFC
▪ 50 Hz to 5 kHz
▪ Small size
▪ Lower inductance
 RFC
▪ Above 10 KHz
▪ Small size
▪ Lower inductance (about 2 mH)
▪ Air core

119.  Tap switching
 Movable core
Refer text (Gupta)

121. References
 Basic electronics (Electronics Engg)--- J B Gupta
 Basic Electronics and Linear Circuits-
N. N. Bhargava, S. C. Gupta, D. C. Kulshreshtha.Tata
McGraw-Hill Education
 https://physicsabout.com/resistor/
 http://www.physics-and-radio-electronics.com/electronic-
devices-and-circuits/passive-components/capacitors
 https://www.electronics-tutorials.ws/inductor/inductor.html
 http://www.electronicshub.org/types-of-inductors-and-
applications/