Introductory electronics

INTRODUCTORY
ELECTRONICS
Passive Electronic Components
C.K. Sunith

Model Engineering College,
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ELECTRONICS
• ELECTRON mechanICS = electronics
• Study of behaviour of an electron under
external applied fields.
• Deals with electron devices and their
utilization (IRE, 1950)
• ELECTRON DEVICE :- a device in which
conduction takes place by movement of
electrons.

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Applications of Electronics
ELECTRONICS
Communication and
Entertainment
Industry Medicine
Line Communication
Defence
Audio Systems
Wireless
Communications
X-Ray
ECG,EMG,
Electrotherapy,,
Electron Microscope
Instrumentation
Radar,
Guided Missiles,,
Coded
Communication.
Automatic Control
Heating & Welding
Computers
Measuring Instrr.
Signal Conditioners
Display Modules
Data Converters
Data Acquisition
Telegraphy
Telephony
Telex
Teleprinters
Radio ,TV,Fax,
Satellite, Mobile
Commn.
PA Systems
Stereo Amp
Record Players
Tape Recorders

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ELECTRONIC COMPONENTS
ELECTRONIC
COMPONENTS
PASSIVE ACTIVE
RESISTORS INDUCTORS
CAPACITORS TUBE DEVICES
SEMICONDUCTOR
DEVICES
FIXED
VARIABLE
FIXED
VARIABLE
FIXED
VARIABLE

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PASSIVE COMPONENTS
• Not capable of amplifying or processing an
electrical signal
• Active components require passive
support
• Resistors, Capacitors and Inductors
• Fixed and Variable Components

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Resistors
• Opposition to current
• Measured in Ohms
• Limit Current
• Divide Voltages
• Introduces Resistance into Circuit
• Provide Load

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RESISTORS
LEADED
CARBON
FILM
METAL
FILM
THICK FILM
THIN FILM
Resistor Family Tree
SMT
METAL
OXIDE
FILM
WIREWOUND
+/-5%
GENERAL
PURPOSE
+/-1%
HIGHER
PERFORMANCE
HIGH POWER
>2W
HIGH POWER
+/-1%
+/-5%
GENERAL
PURPOSE
<+/-1%
SPECIAL
8

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RESISTORS
LEADED
CARBON
FILM
METAL
FILM
THICK FILM
THIN FILM
Resistor Family Tree
SMT
METAL
OXIDE
FILM
WIREWOUND
9
 Mature Market
 Flat Pricing
 Declining Qty’s
 Lowest cost
 Largest Qty’s
 Increasing LT & Pricing for
larger sizes (>0805)
 Higher cost
 Lower volumes
 Performance applic driven

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Resistor Characteristics
• Resistance , Measured in Ohms
• Power Rating , Watts
• Non Polar
• Tolerance %
• Fixed and Variable
• Fixed :- Value cannot be changed
• Variable :- Value can be varied

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Fixed Resistance
• Value Fixed
• Carbon Composition Resistor
• Carbon Film/Metal Film Resistor
• Wire Wound Fixed

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Carbon Composition Resistor
• Carbon Clay composition
• Leads of tinned copper
• Range 1 Ω to 22 MΩ
• Tolerance +/-5% to +/-20%
• Inexpensive
• Small size, Size increases with Wattage Rating
1/10, 1/8, ¼, ½, 1, 2 Watts

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Carbon Composition Resistors
Construction
• Made of finely divided carbon with a powdered
insulating material in suitable proportion
• Resistance Element is a simple rod of pressed
carbon granules, enclosed in insulating plastic
case for mechanical strength
• Ends joined to metal caps with leads of tinned
wire

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Carbon Composition Resistors
• Poor Stability
• Poor Temp. Coefficient -1200 ppm/°C
• Higher Tolerance

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Common Failures
• Open Circuit
• Reasons :
Burning of resistor centre due to excessive
heat
Fracture due to Mechanical Stress
Dislodging of end caps
Wire/lead breakage due to excessive flexing

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Common Failures (2)
• Higher Value
• Reasons :
Heat, Voltage or moisture causing
movement of carbon, binder
Separation of carbon particles due to
swelling caused by moisture absorption

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Film Type Resistors
• Thin Resistive film of Carbon deposited on high
grade Ceramic core.
• Deposited by pyrolysis of hydrocarbon gas on
Ceramic core
• Apprx. Values
• Desired value by trimming layer thickness or
cutting grooves under constant monitoring,
Precise up to 1%
• Fitted with contacts

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Film Type Resistors
• More precise
• Stable
• Low temp Coeff +/- 250 ppm/°C

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Common Failures
• Open Circuit
• Reasons
Scratching / Chipping of film during
manufacture
High voltage/temp causes film
disintegration
Damage to resistance spiral

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Common Failures(2)
• High Noise
• Reasons
Bad contact of end connectors due to
mechanical stress
Poor assembly on the circuit

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Resistor Colour Coding
• For Small Size Resistors < 2W
• 1,2,and/or3 Significant figures
• Significant figures followed by Multiplier,
then tolerance %
• May contain Temp Coeff.

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Colour Coding

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Axial Leaded Styles
Leaded Types
Metal Oxide
Metal Film
Carbon Film
23

Resistors
Values specified in Ohms (Ω),
Kilo-ohms (K), or Mega-ohms
(M)
Marked with value using a color
code 0 1 2 3 4 5 6 7 8 9 5% 10%
Big Bears Run Over Your Gladiola Bed Vexing Garden Worms (go see now)

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Memory Tips : Colour Code
Big Bears Run Over Your Gladiola Bed
Vexing Garden Worms (go see now)
Bill Brown Realized Only Yesterday Good
Boys Value Good Work
Bye Bye Rosie Off You Go Bristol Via Great
Western
BBROYGBVGW

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Body End Dot System
• For Moulded Carbon Composition
Resistors with Radial Leads
• 1,2 – Significant Figures 3 – Multiplier,
4 - Tolerance
2
1
3
4

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Body End Dot System
• Additional Band (usually fifth) indicates
reliability level or failure rate
• Colour Code for Additional Band
Brown 1%, Red 0.1%, Orange 0.01%,
Yellow 0.001%

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Resistor Size

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WIRE WOUND FIXED
• Constructed from a long fine wire, usually
nickel chromium wound on ceramic core
• Length depends on resistance
• Assembly protected with ceramic coating
• Used where large power dissipation and
stable resistances are required
• Values 1 Ω TO 100 KΩ
• Wattages upto 200 W

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WIRE WOUND FIXED
• Value sometimes printed on resistor body
• Tolerance Codes :
F = +/-1% G = +/-2% J = +/-5%
K = +/-10% M = +/-20%
. Examples :
R68M = 0.68 +/-20%, 5K6J = 5.6KΩ +/- 5%
82KK = 82KΩ +/- 10%

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Wirewound Fixed
• Size depends on Power dissipation

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Common Faults
• Open Circuit
• Reasons
-Fracture, Corrosion of Wire due to
moisture absorption
-Slow crystallization of wire due to
impurities
-Disconnection at the welded end

Resistor handling and installation
Resistors are not polarized and may be
installed in either direction.
Resistors are not generally susceptible to ESD
damage, so special precautions are not
required.
Mechanical stress due to lead bending should
be minimized.

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Testing and Measurrement
• Isolate the Component from the Circuit
• Use Multimeter/Ohmmeter of suitable
ranges with probes placed across resistor
leads
• Adjust meter range if necessary
• Replace damaged resistors

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Testing and Measurement

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Variable Resistors
• Potentiometers/Rheostats
• Shaft moves an arm and a contact point
from end to end of the resistance element
• Used for Volume Control, Brightness
Control, Tone Control, Adjustable time&
frequency controls,fan speed control
• Linear and Non Linear

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Potentiometer Construction

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Trim Pots

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Potentiometer Types
• Carbon Pots
Moulded carbon composition
Carbon + Insulating filler onto substrate
. Cermet Pots
Thick film resistance coating onto
ceramic substrate
. Trim pots
Offer fine adjustments
Control of amplification,attenuation,
frequency etc.

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Potentiometers
• Pots Presets & Trimpots

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Potentiometer Types
• Wirewound
Nichrome/Resistance wire wound onto
a suitable insulating former
. Linear : Height of the former is uniform
. Nonlinear : Height of former non uniform
- Sine/Cosine Pot
* Wiper movement follows sine/cosine
laws
* Track length of 360° divided into four 90°
quadrants

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Nonlinear Pots
• Logarithmic Pots
- Wiper movement follows logarithmic laws
- Variation in the second half higher than
in first half

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Wire wound Potentiometers

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Variable Resistors
• Rheostats
- high resistance wire used
- higher current applications, larger in size,
higher power rating
- potential divider(variable) at higher
voltages

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Rheostats
• Covered and uncovered

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Common Failures
• Complete Failure : Open Ckt/Contact
failure b/w wiper and track
• Reasons :
- Corrosion of metal parts by moisture
- Swelling & distortion of plastic parts by
moisture/ high temperature
- Wear and Tear of contact

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Common Failures(2)
• Partial failure
Rise in Wiper contact resistance causes
electrical noise or intermittent contact
• Reasons
- dust, abrasive matter, grease b/w wiper
and track

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Testing and Measurement
• Similar to fixed resistance checks
• Check should be made b/w variable contact and
each of two fixed terminals
• Remedies :
- Replacement
- Cleaning the pot., Cleaner to be sprayed
shaft / openings in the case
- Turn shaft a few times to complete the action
- Replace if problem persists

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Single In-Line Package (“SIP”)
in 4 pin to 13 pin package
Leaded Types
1 2 3 4 5 6 7
Isolated
Common / Bussed 49

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SMT Types
Thick Film Chips
English Metric Length Width
0201 0502 0.5mm (0.02”) 0.25mm (0.01”)
0402 1005 1.0mm (0.04”) 0.5mm (0.02”)
0603 1608 1.6mm (0.06”) 0.8mm (0.03”)
0805 2012 2.0mm (0.08”) 1.2mm (0.05”)
1206 3216 3.2mm (0.12”) 1.6mm (0.06”)
1210 3225 3.2mm (0.12”) 2.5mm (0.10”)
1812 4532 4.5mm (0.18”) 3.2mm (0.12”)
2225 5764 5.7mm (0.22”) 6.4mm (0.25”)
50

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Thick Film Arrays
SMT Types
51

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Capacitors
• To store charge
• Capacitance measured in Farads
• Consists of two plates separated by a dielectric
• Low impedance to ac , high impedance to dc
Xc=(2πfC)-1, inverse proportion to frequency f
• Capacitance C = εrεoA/d
εrεo – permittivities, d – plate separation,
A – plate area

Capacitor ratings
Physical size of capacitors is related to voltage
handling ability – WVDC – working voltage DC
Temperature coefficient may also be important
– can be + or – or nearly zero
Temperature coefficient depends upon
dielectric material

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Capacitor Applications
• Power factor correction
• Motor start and runs
• Welding (Energy storage and quick
discharge)
• Ripple elimination
• Tuning & Timing
• Coupling, Decoupling & Byepass
• Surge suppression

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CAPACITORS
ELECTROSTATIC
CERAMIC FILM ALUMINUM TANTALUM
Markets
ELECTROLYTIC
 Biggest market
 Lowest Cost
 1206 Long LT
 0603 & 0402 good choices
 Better performance at higher cost
 SMT longer LT
 Large Cap in Small Sizes
 Long LT
 Price Increases on C/ D/ E sizes
 Large Cap at low cost
 SMT increasing LT
 Price flat on TH
56

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CAPACITORS
ELECTROSTATIC
CERAMIC FILM ALUMINUM TANTALUM
Capacitor Family Tree
ELECTROLYTIC
• Non polarized
• AC or DC operation
• Lower Capacitance
• Polarized
• DC operation
• Higher Capacitance
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Capacitor Types
CAPACITORS
FIXED VARIABLE
NON
ELECTROLYTIC
ELECTROLYTIC AIR GANG PVC GANG
PAPER CAPACITOR
MICA CAPACITOR
POLYESTER/PLASTIC
CAPACITORS
CERAMIC CAPACITORS
DISC CAPACITORS TUBULAR CAPACITORS
ALUMINIUM
TANTALUM

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TANTALUM
ALUMINUM
FILM
FILM
CERAMIC
CERAMIC
1.0pF 10uF 1000uF
Capacitance Values
F = micro-Farad = 1 x 10-6 F = 1 millionth of a Farad
nF = Nano-Farad = 1 x 10-9 F = 1 billionth of a Farad
pF = Pico-Farad = 1 x 10-12 F = 1 trillionth of a Farad
ALUMINUM
TANTALUM
CERAMIC
FILM
0.10uF
59

Capacitor types
Ceramic disk
Monolithic ceramic
Dipped silvered-mica
Mylar or polyester
Aluminum electrolytic (+/-)
Tantalum (+/-)
Ceramic disk Monolithic ceramic Dipped siver-mica Mylar Mylar
Solid tantalum, polarized Radial aluminum electrolytic Axial aluminum electrolytic

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Paper capacitors
• Two metal foils separated by
paper strips impregnated with
wax, plastic or oil to serve as
dielectric
• Values : 0.0005µF to 2µF
• Voltage rating upto 2000V
• Large physical size
• Low loss
• Leakage resistance upto
1000MΩ
• Longer shelf life without
breakdown

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Mica Capacitors
• Plates of Aluminium/Silver
separated by mica sheets
• Plates connected to two
electrodes
• Capacitance 5 to
10000pF
• Rating upto 500V
• Low leakage, leakage
resistance upto 1000MΩ

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Ceramic Capacitors
• Disc or hollow tube shaped
dielectric made of ceramic
material such as TiO2/Barium
Titanate
• Thin silver compound coated on
both sides of dielectric to serve
as plates
• Leads attached to each side of
disc
• Moisture proof lacquer coating
• Low loss, economical, small size
• Higher voltage ratings

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Ceramic Capacitors
• Capacitance Values
• Low loss (Steatite) 5 pF to 10 nF,
60V to 10KV
Barium Titanate 5 pF to 1µF , 60V to 1 KV
Monolithic 1nF to 47µF, 60 V to 400V
. Tubular 1 to 500pF, Upto 10 KV

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Ceramic Disc Capacitor (Radial)
Cap Value
102 = 1000pF
Dielectric
Y5F
Voltage
1KV = 1000VDC
Cap Tolerance
C = +/-.25pF
D = +/-.5pF
F = +/-1%
G = +/-2%
J = +/-5%
K = +/-10%
M = +/-20%
Z = +80%/-20%
Example shown
P/N: NCD103K1KVY5PTR
Dielectric
Y5P
Cap Value
103 = 0.01uF
Voltage
1KV = 1000VDC
Example shown
P/N: NCD102K1KVY5F 65

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Ceramic caps-Colour codes

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Mica caps-Colour codes

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Colour coding

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Polyester Capacitor
100nF (10x0.01µF) ±20% 400Vdc
• Colour Coding
• First & Second Colours : Digits
• Third Colour : Multiplier
• Fourth Colour : Tolerance
• Fifth Colour : Working Voltage
Brown 100 VDC, Red 250 VDC,
Yellow 400 VDC, Blue 630 VDC,
White 1000VDC

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Capacitance Values – EIA Codes
Pico-Farad Nano-Farad Micro-Farad
EIA Code (pF) (nF) (uF)
1 R 5 1 .5 0 .0 0 1 5
2 R 2 2 .2 0 .0 0 2 2
3 R 3 3 .3 0 .0 0 3 3
4 R 7 4 .7 0 .0 0 4 7
6 R 8 6 .8 0 .0 0 6 8
1 0 0 1 0 0 .0 1
1 5 0 1 5 0 .0 1 5
2 2 0 2 2 0 .0 2 2
2 5 0 2 5 0 .0 2 5
3 3 0 3 3 0 .0 3 3
3 9 0 3 9 0 .0 3 9
4 7 0 4 7 0 .0 4 7
5 6 0 5 6 0 .0 5 6
6 8 0 6 8 0 .0 6 8
7 5 0 7 5 0 .0 7 5
8 2 0 8 2 0 .0 8 2
1 0 1 1 0 0 0 .1 0 .0 0 0 1
1 2 1 1 2 0 0 .1 2 0 .0 0 0 1 2
1 5 1 1 5 0 0 .1 5 0 .0 0 0 1 5
1 8 1 1 8 0 0 .1 8 0 .0 0 0 1 8
2 0 1 2 0 0 0 .2 0 .0 0 0 2
2 2 1 2 2 0 0 .2 2 0 .0 0 0 2 2
2 7 1 2 7 0 0 .2 7 0 .0 0 0 2 7
3 0 1 3 0 0 0 .3 0 .0 0 0 3
3 3 1 3 3 0 0 .3 3 0 .0 0 0 3 3
3 9 1 3 9 0 0 .3 9 0 .0 0 0 3 9
4 7 1 4 7 0 0 .4 7 0 .0 0 0 4 7
5 1 1 5 1 0 0 .5 1 0 .0 0 0 5 1
5 6 1 5 6 0 0 .5 6 0 .0 0 0 5 6
6 8 1 6 8 0 0 .6 8 0 .0 0 0 6 8
7 5 1 7 5 0 0 .7 5 0 .0 0 0 7 5
8 2 1 8 2 0 0 .8 2 0 .0 0 0 8 2
1 0 2 1 0 0 0 1 0 .0 0 1
3 digit code
(pF)
TANTALUM
CERAMIC
FILM
3 digit code
First 2 digits are significant.
Third digit is number of zeros.
101 = 100pF
3 digit code
“R” represents decimal point
4R7 = 4.7pF
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Capacitance
Values
–
EIA
Codes
1 2 2 1 2 0 0 1 .2 0 .0 0 1 2
1 5 2 1 5 0 0 1 .5 0 .0 0 1 5
2 0 2 2 0 0 0 2 0 .0 0 2
2 2 2 2 2 0 0 2 .2 0 .0 0 2 2
2 7 2 2 7 0 0 2 .7 0 .0 0 2 7
3 0 2 3 0 0 0 3 0 .0 0 3
3 3 2 3 3 0 0 3 .3 0 .0 0 3 3
3 9 2 3 9 0 0 3 .9 0 .0 0 3 9
4 7 2 4 7 0 0 4 .7 0 .0 0 4 7
5 6 2 5 6 0 0 5 .6 0 .0 0 5 6
6 8 2 6 8 0 0 6 .8 0 .0 0 6 8
8 2 2 8 2 0 0 8 .2 0 .0 0 8 2
1 0 3 1 0,0 0 0 1 0 0 .0 1
1 2 3 1 2,0 0 0 1 2 0 .0 1 2
1 5 3 1 5,0 0 0 1 5 0 .0 1 5
1 8 3 1 8,0 0 0 1 8 0 .0 1 8
2 2 3 2 2,0 0 0 2 2 0 .0 2 2
3 3 3 3 3,0 0 0 3 3 0 .0 3 3
4 7 3 4 7,0 0 0 4 7 0 .0 4 7
5 6 3 5 6,0 0 0 5 6 0 .0 5 6
6 8 3 6 8,0 0 0 6 8 0 .0 6 8
8 2 3 8 2,0 0 0 8 2 0 .0 8 2
1 0 4 1 0 0,0 0 0 1 0 0 0 .1 0
1 2 4 1 2 0,0 0 0 1 2 0 0 .1 2
1 5 4 1 5 0,0 0 0 1 5 0 0 .1 5
2 2 4 2 2 0,0 0 0 2 2 0 0 .2 2
3 3 4 3 3 0,0 0 0 3 3 0 0 .3 3
4 7 4 4 7 0,0 0 0 4 7 0 0 .4 7
5 6 4 5 6 0,0 0 0 5 6 0 0 .5 6
1 0 5 1,0 0 0,0 0 0 1 0 0 0 1 .0
2 2 5 2,2 0 0,0 0 0 2 2 0 0 2 .2
3 3 5 3,3 0 0,0 0 0 3 3 0 0 3 .3
4 7 5 4,7 0 0,0 0 0 4 7 0 0 4 .7
6 8 5 6,8 0 0,0 0 0 6 8 0 0 6 .8
1 0 6 1 0,0 0 0,0 0 0 1 0,0 0 0 1 0
2 2 6 2 2,0 0 0,0 0 0 2 2,0 0 0 2 2
104 = 100,000pF
104 = 100nF
104 = 0.1uF
106 = 10,000,000pF
104 = 10,000nF
104 = 10uF
103 = 10,000pF
103 = 10nF
103 = 0.01uF
3 digit code
(pF)
TANTALUM
CERAMIC
FILM
71

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Capacitance Values – EIA Codes
R10 100,000 100 0.1
R22 220,000 220 0.22
R33 330,000 330 0.33
R47 470,000 470 0.47
1R0 1,000,000 1 0 0 0 1
2R2 2,200,000 2 2 0 0 2.2
3R3 3,300,000 3 3 0 0 3.3
4R7 4,700,000 4 7 0 0 4.7
100 10,000,000 1 0,0 0 0 10
220 22,000,000 2 2,0 0 0 22
330 33,000,000 33,000 33
470 47,000,000 47,000 47
101 100,000,000 100,000 100
221 220
331 330
471 470
102 1000
222 2200
332 3300
472 4700
103 10,000
223 22,000
333 33,000
473 47,000
3 digit code
(uF)
3 digit code
First 2 digits are significant.
Third digit is number of zeros
471 = 470uF
3 digit code
“R” represents decimal point
R33 = 0.33uF
ALUMINUM
72

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Tolerance
Capacitance Tolerance :
The allowable window - limits that the capacitors’ +25°C
(room temperature) capacitance value will be within.
1 digit code
ALUMINUM
TANTALUM
CERAMIC
FILM
CERAMIC
FILM
CERAMIC
CERAMIC
CERAMIC
73

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Electrolytic Capacitors
• Electrolyte (Borax/Carbon Salt) as negative
plate, aluminium plate as contact
• Aluminium positive plate
• Extremely thin insulating film of Al2O3 as
dielectric medium electrochemically deposited
on anode surface
• Absorbent gauze saturated with electrolyte is
kept in contact with dielectric
• Polarity, No reverse voltages to avoid damages
• low leakage resistance, large sizes
• High Capacitance Values 1µF to 10000µF, 1V to
500V -20 to 50% tolerances
• Values printed on the surface

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Electrolytic Capacitors

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SMT Electrolytic Capacitors
• Cathode (-) & Anode (+) markers
• Capacitance value (µF)
• Voltage rating (VDC)
• Date Code
Appearance
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Surface Mount Tantalum Electrolytic Capacitors
Case Code Metric English Length Width
P 2012 0805 2.0mm (0.08”) 1.2mm (0.05”)
A, A2 3216 1206 3.2mm (0.12”) 1.6mm (0.06”)
B, B2 3528 1411 3.5mm (0.14”) 2.8mm (0.11”)
C 6032 2412 6.0mm (0.24”) 3.2mm(0.12”)
D1* 5846 2318 5.8mm (0.23”) 4.6mm(0.18”)
D, E 7343 2917 7.3mm (0.29”) 4.3mm (0.17”)
* - D1 is Japanese size
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Variable Capacitors
• Air Gang ,PVC Gang Condensors for
manual tuning of station in radio receivers
• Trimmers and Padders for fine tuning in
receiver circuits
• Area of Stator is fixed, By turning rotor
amount of plate surface (area) exposed is
varied causing change in Capacitance
value

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Air Gang Condensors
• Turn rotor with the help of knob,
rotor plate moves I or out of stator
plates
• Capacitance is maximum when
rotor plates are fully in
• C=(n-1)εoA/d, n – no. of plates, d-
separation b/w two adjacent
plates
• Two or more capacitors ganged,
controlled by single knob

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Gang Condensors
• Air Gang or PVC Gang – classification
based on dielectric material used
• Used for station tuning in radio receivers
• Air gang found in manually tuned old valve
radio receivers

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Trimmers and Padders
• Fine adjustments using screws.
• As screw is turned inward, plates
are compressed, capacitance
increased
• two small flexible metal plates
separated by air/mica/ceramic
slab as dielectric
• Trimmers 5pF to 30pF variable
• Padders 10 – 500 pF
• Padders have more plates and
somewhat larger size

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Common Failures in Capacitors
• Performance degradation
- Gradual fall in insulation resistance, rise
in leakage current/series resistance,
losses, increased dissipation factor
. Complete failure
Open ckt due to end connection failure,
damage during assembly, Short ckt
due to dielectric breakdown

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Reasons for failure
• Environmental factors
Mechanical shocks and vibration, Thermal
shocks,High humidity
. Misuse
poor assembly, prolonged storage, overvoltage,
wrong polarity use
. Manufacturing defects
Impurities in electrolytes, mechanical damage to
end spray of metallised capacitors resulting in
overheating and open ckt.

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Indications
• Good : Slow Charging to high
resistnce value, Slow meter
movement to high
• Short : Meter moves to zero,
stays there
• Open : Meter stays at highest
value
• Leaky : Meter moves to low
resistance, comes up and show
reading less than normal

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Remedies
• Switch off the equipment
• Isolate the component
• Allow discharge
• Ohmmeter/Multimeter(preferably analog)
in highest Ohms range. Meter voltage not
to exceed rated voltage
• Measuring Values : Using Capacitance
meter, LCR meters in Capacitance range

Capacitor handling and
installation
Most capacitors are not polarized and may be installed
in either direction.
Electrolytic capacitors ARE polarized and MUST be
installed with proper polarity, else catastrophic failure!
Capacitors are not generally susceptible to ESD
damage, so special precautions are not required.
Mechanical stress due to lead bending should be
minimized.

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INDUCTORS

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Inductance
• Opposition of magnetic field to change in current
• Measured in Henrys, L =µrµ0AN2/l , A-core area,
N – no. of turns, µr&µ0 – permeabilities, l – core
length
• Force trying to keep current steady is called
induced emf
• Electronic component producing inductance L is
called inductor
• Opposes ac, passes dc, XL=2πfL f- frequency
• Used as Filters, Antenna coils, Transformers etc.

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Inductors
AIR CORE
FERRITE
CORE
IRON CORE
INDUCTOR

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AIR CORE INDUCTORS
• Wire wound on cardboard former
• Air inside the coil
• Least inductance µH or mH
• No core losses at any freq
• Used as inductive loads

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IRON CORE INDUCTORS
• Coil wound over laminated iron core
• Lamination reduces losses, Iron
laminations are pressed together with
insulation in between
• Inductance also depends on
permeability of iron
• Efficient at low frequency, low losses at
minimal frequency, but increases with
frequency
• Larger inductance 1 – 25 H
• Eg : Filter chokes, Transformers

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Ferrite Core Inductors
• Coil wound over ferrite core
• Ferrite consists of fine
particles of iron powder
embedded in an insulating
binder
• Minimum losses at high
frequencies
• High Inductance values of
several µH
• Eg : Antenna coils , IFT

Inductor types
Molded inductor & air-wound inductor Adjustable air-wound inductor
Ferrite core toroidal transformer Iron powder toroidal inductor
Air wound inductor

Inductor ratings
Wire gauge and physical size of the coil
determine the current handling capacity.
Core material will have a temperature
dependence. Air is best, followed by iron
powder, then ferrites.

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INDUCTOR EXAMPLES
• Filter Chokes :
To smoothen pulsating current (filtering)
Core made of laminated E & I shaped
sheets
Range 5 – 20 H, Current upto 0.3 A
• AF chokes :
High Impedance at audio freq (60Hz –5KHz)
Smaller size , Lower inductances
• RF chokes :
Used at high freq, disallows radio frequencies

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Varying Inductance
• Use of tapped coils
• Slider contacts to vary
turns
eg:autotransformers
• Permeability tuning :
Ferrite slug screwed
in and out of coil
eg : IFTs,Antenna
coils

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Inductor Testing and Measurement
• Open circuit : By continuity check
with Ohmmeter/ Multimeter
• Shorted/Partially shorted : Found
by inspecting high frequency
response. Partial shorting reduces
high frequency roll off
• Measurement : Using
LCR/Inductance meter,
Experimental calculation using
bridge circuits(Maxwell, Hay,
Owens)

Inductor handling and
installation
Inductors are not polarized and may be installed in
either direction.
Inductors are not generally susceptible to ESD
damage, so special precautions are not required.
Mechanical stress due to lead bending should be
minimized.
Inductors in timing or frequency determining circuits
should be installed in a mechanically rigid fashion.

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In Store …….

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Introductory electronics

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Introductory electronics