TEJAS SHAH

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BASIC ELECTRONICS (17213)

THEORY EXAM – 100 MARKS

TERM WORK – 025 MARKS

TOTAL MARKS – 125 MARKS

CONTENTS:

NOTES PREPARED BY:

TEJAS SHAH

1. Introduction to Passive Circuit Elements 08 MARKS

2. Semiconductor Diode 24 MARKS

3. Rectifiers, Filters and Regulators 16 MARKS

4. Transistors 24 MARKS

5. Amplifiers and Oscillators 24 MARKS

6. Integrated Circuits 04 MARKS

TEJAS SHAH

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CHAPTER 1: Introduction to Passive Circuit Elements

(08 MARKS)

1.1 DEFINITION & INTRODUCTION TO ELECTRONICS:

Electronics deals with electrical circuits that involve active electrical

components such as vacuum tubes, transistors, diodes and integrated

circuits, and associated passive interconnection technologies.

The nonlinear behavior of active components and their ability to control

electron flows makes amplification of weak signals possible and

electronics is widely used in information processing, telecommunications

and signal processing.

The ability of electronic devices to act as switches makes digital

information processing possible.

Interconnection technologies such as circuit boards, electronics packaging

technology, and other varied forms of communication infrastructure

complete circuit functionality and transform the mixed components into a

working system.

Electronics device can be defined as “A device in which conduction

takes place by movement of electron through a vacuum, gas or a

semiconductor.”

Definition of electronics:

The Institute of Radio Engineers (IRE) has given standard definition of

electronics, according to that Electronics is a field of science &

engineering, which deals with electronics devices & their utilization.

The electronics has great importance in today’s world as electronics

devices are capable of doing many functions.

Some of the functions are listed below:

1. Rectification 4. Amplification

2. Controller 5. Generation

3. Conversion of light in to electrical

signal.

6. Conversion of electrical signal in

to light.

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1.2 APPLICATION OF ELECTRONICS:

Electronics has made tremendous advancement during last few decades and our

day to day life involves the use of electronic devices. Electronics has played a

major role in every sphere of our life; this can be proved with the

following application of electronics:

Entertainment and Communication:

Availability of economical and fast means of communication paves the way for

progress of a country. Few decades ago, the main application of electronics was

in the field of telephony and telegraphy. Radio and TV broadcasting offers a

means of both entertainment as well as communication.

Defense Applications:

Defense applications are completely controlled by electronic circuits. RADAR

that is Radio Detection and Ranging is the most important development in

electronics field. With the help of radar it is possible to detect and find the exact

location of enemy aircraft. Radar and anti craft guns can be linked by an

automatic control system to make a complete unit.

Industrial Application:

Electronics circuits are widely being used in industrial applications such as

control of thickness, quality, weight and moisture content of a material.

Electronic amplifier circuits are used to amplify signals and thus control the

operations of automatic door openers, power systems and safety devices.

Electronically controlled systems are used for heating and welding in the

industry. The most important industrial application is that the power stations

which generate thousands of megawatts of electricity are controlled by tiny

electronic devices and circuits.

Medical Services:

Electronics systems are being used by Doctors and scientists in the diagnosis

and treatment of various diseases. X-rays, ECG, Short eave diathermy units and

oscillographs are some instruments which have been used so far in medical

science. The use of electronics in medical science has grown so extremely and

is useful in saving the life of mankind from a lot of sufferings.

Instrumentation: Electronics instruments such as cathode-ray oscilloscopes, frequency counters,

signal generators, strain gauges are of great help in for precise measurement of

various quantities. Without these electronic instruments no research laboratory

is complete.

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1.3 TYPES OF ELECTRONIC COMPONENT

The components used in designing or assembling of an electronic circuit are

called ELECTRONIC COMPONENTS.

CLASSIFICATION OF ELECTRONIC COMPONENTS:

Passive Components:

Resistors, capacitors and inductors are called as passive components. These

electronics components are called passive because they by themselves are not

capable of amplifying or processing an electrical circuit. However, passive

components are as important as active components in any electronic circuit.

The components which conduct current in both the direction are called as

bidirectional devices.

E.g.: Resistors, Capacitors, and Inductors.

Active Components:

Active components are that type of components which required some bias

voltage to operate. The components which produce the energy in the form of

current or voltage are called as active components. They by themselves are

capable of amplifying or processing an electrical circuit.

The components which conduct current in one direction only are called as

unidirectional devices.

E.g.: Electronic tubes & semiconductor devices such as diodes, transistors,

FETs, UJTs etc.

ELECTRONICS

COMPONENT

PASSIVE

COMPONENTS

ACTIVE

COMPONENTS

RESISTORS

CAPACITORS

INDICTORS

ELECTRONIC

TUBES

SEMICONDUCTOR

DEVICES

DIODES

TRANSISTORS

FIELD EFFECT

TRANSISTORS

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COMPARISON BETWEEN ACTIVE & PASSIVE COMPONENTS:

PASSIVE COMPONENTS ACTIVE COMPONENTS

1 The electronics components are

called passive because they by

themselves are not capable of

amplifying or processing an

electrical circuit.

The electronics components are

called active because they by

themselves are capable of

amplifying or processing an

electrical circuit.

2 It does not introduce any gain.

It may introduce any gain.

3 It has bidirectional functions.

It has unidirectional functions.

4 These components do not act as an

energy source.

These components acts as an energy

source

5 E.g.: Resistors, Capacitors, and

Inductors.

E.g.: Electronic tubes &

semiconductor devices such as

diodes, transistors, FETs, UJTs etc.

1.4 TYPES OF PASSIVE COMPONENTS

1.4.1 RESISTORS

CONCEPT OF RESISTANCE OR DEFINITION OF RESISTANCE:

The opposition to the flow of current through any material is called

resistance. & the device having this property is called Resistor.

Resistor is a component which can conduct current in both the direction &

therefore known as bidirectional device.

The resistance of a given object depends primarily on two factors: What

material it is made of, and its shape. For a given material, the resistance is

inversely proportional to the cross-sectional area; for example, a thick

copper wire has lower resistance than an otherwise-identical thin copper

wire. Also, for a given material, the resistance is proportional to the length;

for example, a long copper wire has higher resistance than an otherwise-

identical short copper wire. It can be computed as

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where is the length of the conductor, measured in meters [m], A is the cross

Section area of the conductor measured in square meters [m²], and ρ (rho) is

the electrical resistivity (also called specific electrical resistance) of the

material, measured in ohm-meters (Ω·m).

The SI unit of electrical resistance is the ohm (Ω).

SYMBOL OF RESISTOR:

FIXED RESISTOR VARIABLE RESISTOR

FECTORS AFFECTING RESISTANCE:

Cross-sectional area of the wire.

Length of the wire.

Temperature.

Nature of Material

General Specifications of Resistors:

Maximum voltage rating:

The maximum voltage at which the resistor can operate without failure is called

maximum voltage rating. OR

The maximum voltage that can be applied to a resistor without any damage to it

is called the voltage rating and it is given by.

Vmax = (Power rating × Resistance value) ½

Vmax = (P×R) ½

Power Rating:

The maximum amount of heat dissipated by a resistor at maximum specified

temperature without damage to resistor is called power rating of a resistor.

It is expressed in watt (W) at specified temperature.

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Temperature coefficient of resistance:

It is defined as the percentage change in resistance per unit change in

temperature. It is denoted by letter “alpha (α)”.

The temperature coefficient can be positive or negative depending upon whether

resistance increases or decreases with temperature.

Temperature coefficient (α) = (RT1 – RT2) ×106 (Ppm /ºc)

R× (T1-T2)

Where; Rt1 = value of resistance at temperature T1ºC.

Rt2 = value of resistance at temperature T2 ºC.

Tolerance:

The tolerance means that the actual value of the resistor may be either larger or

smaller than that of the indicated value by a factor given by specified tolerance.

Operating Temperature:

The maximum temperature at which the resistor can be operated without failure

is called maximum operating temperature. It is also called temperature rating.

Wattage:

The wattage of a resistor is the power handling capacity of a resistor. It can

dissipate without excessive heating. The power rating of a resistor is given in

wattage. The normal available resistors have power ratings of 1/8 W, ¼ W, ½

W, 1W, 2W.The size of a resistor depends on its power handling capacity.

Resistivity (or specific resistance):

It is defined as the resistance of the piece of that material which is 1 meter long

and of unit cross sectional area.

Frequency Range:

The range of frequency up to which the resistor offers pure resistance, is called

frequency range. The resistor may be pure resistor at low frequency as it offers

only resistance, but it may have capacitive or inductive impedance at high

frequencies.

Shelf life:

It is defined as the change in value of resistance during storage usually quoted

for 1 year.

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Load Life:

It is defined as the change in value of resistance after specified time at specified

temperature. Resistors are tested for change in resistance after 1000 hours at

70ºc.

CLASSIFICATION OF RESISTORS:

Linear Resistors:

The resistors, through which the current is directly proportional to the

applied voltage, are called linear resistors. Such resistors have a property

that their resistance value do not change with the variation in applied

voltage, temperature or light intensity.

The linear resistors are of two types namely fixed resistors and variable

resistors.

Fixed Resistors:

The fixed resistors are those, whose values do not change with the

variation in applied voltage, temperature or light intensity. Such resistors

are available in various shapes and sizes, with both axial and radial leads

as shown below.

RESISTORS

LINEAR

RESISTORS

NON-

LINEAR

RESISTORS

FIXED

RESISTORS

VARIABLE

RESISTORS

CARBON COMPOSITION

WIRE

WOUND

THICK

FILM

THIN FILM

POTENTIO

METER

TRIMMER

WIRE

WOUND

THERMISTER

(TDR)

PHOTO

RESISTOR

(LDR)

VARISTOR

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The fixed resistors are of following types:

Carbon Composition Resistor.

Thin film Resistor.

Thick film Resistor.

Wire-wound Resistor.

Carbon Composition Resistor

Concept:

The type of resistor is manufactured in both, insulated and the uninsulated

form. The uninsulated type allows better heat dissipation and the

insulated one avoids any possibility of short circuit to the adjacent

components and metal chassis.

It is made of carbon dust or graphite paste, low wattage values

The construction of a moulded (insulated) carbon composition resistor is

shown below.

Construction:

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These resistors are made by mixing carbon powder and insulating binders

to produce the desire value of resistors.

The resulting resistance values are within ± 10% of the desired value.

However, the resistors with ± 5% tolerance are also obtained through

special techniques.

Usually, the resistance element is a simple rod of carbon powder, which

is enclosed in a plastic case for insulation and mechanical strength.

The two ends of the carbon resistance element are joined to metal caps

with leads of tinned wire. The leads are provided for soldering the resistor

into the circuit.

The carbon composition resistors are available in resistance values

ranging 1Ω to 22 MΩ and power ratings of. The size of these resistors

varies with the power ratings.

Applications:

Used in Regulated Power supply

Used in Multimeter

Used in Wheatstone Bridge

Used when high power handling capacity is required in small size.

Wire- Wound Resistors:

Concept:

The power handling capacity of carbon composition resistors is very low. Power

handling capacity of wire-wound resistors is much higher than the carbon

composition resistors.

Construction:

The construction of this type of resistor is also very simple. In wire

wound resistor a wire of manganin or constantan is wound around a

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cylinder of insulated material. The resistance of these two materials is

almost zero. So there would no resistance variation with temperature.

The wounded wire is covered with an insulating material such as baked

enamel. This cover of insulating heat resistive material is provided to

resist the effect of ambient temperature variation.

Different sizes and ratings of wire wound resistor can easily be achieved

by using different lengths and diameters of the wire.

These resistors are easily available for wide range of ratings. The range of

resistance values varies from 1 Ω to 1 MΩ. Typical tolerance limit of

these resistors varies from 0.01 % to 1 %.

They can be used for high power applications of 5 to 200 W dissipation

ratings.

The cost of these resistors is much higher than carbon resistor. Normally

wire wound resistor is used where carbon composition resistor cannot

meet the purpose because of its limitations.

Applications:

Zener Voltage Regulator.

Power Amplifiers.

High power resistors in DC power supplies.

High power circuits in radio and TV receivers.

Low frequency, high power applications.

Film type Resistors:

The film type resistors are as follows

Carbon film resistor

Metal film resistor

Cermet resistor (Thick film resistors)

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Carbon film Resistors:

Concept:

The resistive film deposited on the glass or ceramic rod is of pure carbon

that is why they are called as carbon film resistors.

The thickness of the film will decide the value of the resistor.

Spirally is done in order to adjust the value of resistor.

Construction:

During manufacture, a thin film of carbon is deposited onto a small

ceramic rod. The resistive coating is spiraled away in an automatic

machine until the resistance between the two ends of the rod is as close as

possible to the correct value.

Metal leads and end caps are added; the resistor is covered with an

insulating coating and finally painted with coloured bands to indicate the

resistor value.

Carbon film resistors are cheap and easily available, with values within

±10% or ±5% of their marked or 'nominal' value.

Metal film and metal oxide resistors are made in a similar way, but can be

made more accurately to within ±2% or ±1% of their nominal value.

There are some differences in performance between these resistor types,

but none which affect their use in simple circuits.

Applications:

All types of precision equipments

Used in defense communication

Used in industrial control

Used in computers

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Metal Film Resistors:

Concept:

These resistors are made by depositing a very thin layer of metal on ceramic or

glass rod. The metal film is spiral cut to the desired resistance. These resistors

have tolerances ranging from ± 0.025% to 2%, of the desired value.

Types of metal film resistors:

Nickel chromium resistors

Metallic oxide film resistors

Cermets

Applications:

These resistors are used for the applications that need better stability,

better reliability and long life. The applications are transmitter,

modulators and demodulators, oscillators, feedback amplifiers etc.

Types of Colour Codes:

Depending upon the number of colour band used, the resistor colour

codes can be classified into following types:

Three band colour code.

Four band colour code.

Five band colour code.

Six band colour code.

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Non- Linear Resistors:

The resistors, through which the current is not directly proportional to the

applied voltage, are called non-linear resistors. Such resistors have a

property that their resistance values change with the variation in applied

voltage, temperature or light intensity.

The non-linear resistors are of three types namely thermistor, photo-

resistor and varister.

Light Dependent Resistor (LDR):

Concept:

When the light is incident on the semiconductor materials, the covalent

bonds are broken and the charge carriers i.e. electron hole pairs are

produced.

The amount of intensity light on the surface of the semiconductor

material determines the no. of electron-hole pair generated.

As the light intensity increases, conductivity of semiconductor material

increases and thus the resistance decreases.

Thus, the resistance of the material varies inversely with the amount of

light intensity.

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Construction:

These are made in disc shapes with wire lead end on one side.

They have ceramic substrate over which layer of cadmium sulphide (cds)

or lead sulphide (pbs) is deposited in zigzag form to increase the length

hence resistance value increases.

Depending upon the layer the resistance changes.

Electrodes are formed by evaporating metal in vaccum .Leads are

connected and put in plastic case as shown in fig above.

Symbol:

Applications:

It is used in burglar alarm to give alarming sound when a burglar invades

sensitive premises.

It is used in street light control to switch on the lights during dusk and

switch off during dawn automatically.

It is used in Lux meter to measure intensity of light in Lux.

It is used in photo sensitive relay circuit.

Temperature Dependent Resistor (TDR):

Concept:

Temperature dependent resistors are also called as Thermistors.

The word thermistor is an acronym for thermal resistor i.e. a temperature

–sensitive-resistor. It is used to detect very small changes in temperature.

The variation in temperature is reflected through an appreciable variation

of the resistance of the device.

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Thermistors with both Negative temperature coefficient (NTC) and

Positive temperature coefficient (PTC) are available.

NTC means that the resistance decreases with the increase in temperature.

PTC means that the resistance increases with the increase in the

temperature.

Symbol:

Characteristics:

Construction:

Thermistors are manufactured in the form of beads, probes, discs,

washers and rods.

They are useful where temperature sensing must be done in a limited

space.

NTC Thermistors:

NTC means that the resistance decreases with the increase in temperature.

NTC thermistors are manufactured by sintering (it is a process in which

powered materials are fused together by the application of heat)

semiconductor ceramic materials prepared from mixtures of metallic

oxides of cobalt, nickel, manganese etc.

These materials have high negative temperature coefficient.

NTC thermistors offer mechanical, thermal and electrical stability

together with high degree of sensitivity.

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NTC have inversely proportional relationship between resistance and

temperature and characteristic curve.

R α 1/T NTC thermistor can operate over +200°C to +1000°C.

Applications:

For temperature measurement and control.

Temperature compensation.

Fluid flow measurement.

PTC Thermistors:

PTC means that the resistance increases with the increase in the

temperature.

PTC semiconductors are made from doped barium titanate

semiconducting material.

This material have very large change is resistance for a small change in

temperature.

PTC thermistors are used when a drastic change in resistance is required

at specific temperature.

PTC thermistors operate over 60°C to 180°C.

PTC has directly proportional relation between temperature and

resistance and the characteristic curve.

T α R.

Applications:

Temperature sensing in electrical motors and transformers protection.

Liquid level sensor.

To protect solid state fuse against excess current.

Voltage Dependent Resistor (VDR):

Concept:

A Voltage Dependent Resistor is an electronic component with a

"diode-like" nonlinear current–voltage characteristic.

VDR are often used to protect circuits against excessive

transient voltages by incorporating them into the circuit in such a way

that, when triggered, they will shunt the current created by the high

voltage away from sensitive components.

A Voltage Dependent Resistor is also known as varistor.

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A varistor’s function is to conduct significantly increased current when

voltage is excessive.

Symbol:

Symbol of VDR.

Characteristics:

The most common type of varistor is the metal-oxide varistor (MOV).

This contains a ceramic mass of zinc oxide grains, in a matrix of other

metal oxides (such as small amounts of bismuth, cobalt, manganese)

sandwiched between two metal plates (the electrodes).

The boundary between each grain and its neighbor forms a

diode junction, which allows current to flow in only one direction.

The mass of randomly oriented grains is electrically equivalent to a

network of back-to-back diode pairs, each pair in parallel with many

other pairs.

When a small or moderate voltage is applied across the electrodes, only a

tiny current flows, caused by reverse leakage through the diode junctions.

When a large voltage is applied, the diode junction breaks down.

The result of this behavior is a highly nonlinear current-voltage

characteristic, in which the MOV has a high resistance at low voltages

and a low resistance at high voltages.

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1.5 INDUCTORS

FARADAY’S LAW OF ELECTROMAGNETIC INDUCTION:

FARADAY’S FIRST LAW OF ELECTROMAGNETIC

INDUCTION:

Statement:

This law states that when magnetic flux linking with the coil (or

conductor) changes, the e.m.f. is induced in the coil (or conductor).

OR

When a conductor cuts the magnetic flux, the e.m.f. is induced in the conductor.

FARADAY’S SECOND LAW OF ELECTROMAGNETIC

INDUCTION:

Statement:

This law states that magnitude of induced e.m.f. is directly proportional to

the change of magnetic flux linkage.

OR

The magnitude of induced e.m.f. is directly proportional to the product of

number of turns and rate of the change of magnetic flux linkage with the coil.

Induced e.m.f. α rate of change of flux linkage.

e α number of turns× Rate of change of flux.

Symbol:

Unit of inductance is Henry

Specification of Inductor:

Inductor specifications normally include

The value of inductance (expressed in H, mH, μH, or nH).

The current rating (i.e., the maximum current which can be continuously

applied to the inductor under a given set of conditions).

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The accuracy or tolerance (quoted as the maximum permissible

percentage deviation from the marked value).

Other considerations may include the temperature coefficient of the

inductance (usually expressed in parts per million, ppm, per unit

temperature change), the stability of the inductor, the d.c. resistance of

the inductor windings (ideally zero), the Q-factor (quality factor) of the

inductor.

CLASSIFICATION OF INDUCTORS:

1.6 CAPACITOR

DEFINATION OF CAPACITANCE:

Capacitance is the ability (or property) of capacitor, which opposes the

changes in voltage by means of energy storage in the form of Electrostatic

energy.

Consider any two parallel conducting plates, separated by an insulating medium

called dielectric, connected across the DC voltage source as shown below.

INDUCTORS

FIXED VARIABLE

AIR CORE CORED

IRON CORE FERRITE CORE

SLUG TUNNED TAPPED

D

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If the voltage is applied, the metal plates start charging.

As the applied voltage across plate is constant, the electric charge ‘Q’ across the

metal plate is also constant.

Q α V

Q = CV

C = Q

V

C = Proportionality constant & called as capacitance

Q = Electric charge in coulomb

V = applied voltage in volts.

For a parallel plate capacitor,

C α ε.A OR C= ε0 .ε. A

D D

Definition:

Electrical or electronic device that (like a battery) stores electric current for

releasing it at a specific time or rate but (unlike a battery) does not generate it.

Also called as condenser.

In other words, a capacitor is an electrical device for storing charge. In

general, capacitors are made from two or more plates of conducting material

separated by a layer or layers of insulators. The capacitor can store energy to be

given to a circuit when needed.

Symbol:

Capacitance is measured in terms of farads.

Specification of capacitor:

Working Voltage (WV):

The Working Voltage is the maximum continuous voltage either DC or AC

that can be applied to the capacitor without failure during its working life.

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Generally, the working voltage printed onto the side of a capacitors body refers

to its DC working voltage, (WV-DC).

Equivalent Series Resistance, (ESR):

The Equivalent Series Resistance or 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.

Nominal Capacitance, (C):

The nominal value of the Capacitance, C of a capacitor is measured in pico-

Farads (pF), nano-Farads (nF) or micro-Farads (µF) and is marked onto the

body of the capacitor as numbers, letters or colored bands.

Tolerance, (±%):

As with resistors, capacitors also have a Tolerance rating expressed as a plus-

or-minus value either in Pico farad’s (±pF) for low value capacitors generally

less than 100pF or as a percentage (±%) for higher value capacitors generally

higher than 100pF.

Leakage Current:

The dielectric used inside the capacitor to separate the conductive plates is not a

perfect insulator resulting in a very small current flowing or "leaking" through

the dielectric due to the influence of the powerful electric fields built up by the

charge on the plates when applied to a constant supply voltage. This small DC

current flow in the region of nano-amps (nA) is called the capacitors Leakage

Current.

Working Temperature, (T):

Changes in temperature around the capacitor affect the value of the capacitance

because of changes in the dielectric properties.

The normal working range for most capacitors is -30°C to +125°C with nominal

voltage ratings given for a Working Temperature of no more than +70°C

especially for the plastic capacitor types.

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CLASSIFICATION:

CAPACITOR

FIXED

VARIABL

E

ELECTRO

LYTIC

ELECTRO

STATIC

TANTALUM

ALUMINIUM

PLAIN

FOIL

ETCHED

FOIL

CERAMIC

MICA

PLASTIC

PAPER

CERAMIC

AIR

MICA

PLASTIC