CONDUCTOR
INSULATOR
SEMICONDUCTOR
The elements which
allow the flow of
electric current
through it by the
application of
voltage.
Good conductor.
The elements which
do not allow any
flow of electric
charge.
The elements whose
conductivity lies
between insulators
and conductors.
Bad conductor.
Wood, Rubber,
Glass, Ebonite, Mica,
Sulphur, Dry air.
Energy Band.
Copper, Mercury,
Silver, Al, Water,
Acids, Human Body,
Metallic Salt,
Charcoal.
Conduction band and
valence band overlap
each other.
At 0K works, it
works as an insulator
while by applying
thermal agitation or
by adding impurity
becomes good
conductor.
Germanium, Silicon,
Cotton, Wool,
Marble, Sand, Paper,
Ivory, Moist air.
Conduction band and
valence band are
separated by 6eV.
Conduction band and
valence band
separated by 1eV.
Temperature
Coefficient.
Positive temperature
Coefficient of
resistance.
Negative
Temperature
Coefficient of
resistance.
They do not contain
any charge carriers.
Negative
Temperature
Coefficient of
resistance.
Intrinsic charge
carriers are holes and
electrons.
Current flow due to
electrons.
Current does not
flow.
Current flow due to
holes and electrons.
Very High.
Negligible.
Low.
Valence band and
conduction band is
completely filled.
Valence Band is
completely filled and
conduction band is
completely empty.
Valence band is
partially empty and
conduction band is
partially filled.
BASIS FOR
COMPARISON
Definition.
Electric
Conductivity.
Examples.
Electrons.
Charge carriers.
Current Flow.
Number of Charge
Carriers.
Valence band and
conduction Band.
Effect of
temperature on
conductivity.
On Increasing
Temperature.
Conductivity
decreases.
Conductivity
Increases.
Conductivity
Increases.
The number of
current carriers
decreases.
The number of
current carriers
increases.
The number of
current carriers
increases.
Resistance Increases.
Resistance remain
unchanged.
Resistance
Decreases.
Takes place easily.
Does not take place.
Very Slow.
Behaves like super
conductor.
Behaves like an
Insulator.
Behaves like an
Insulator.
Ionic bond.
Ionic Bond and
Covalent Bond.
Covalent Bond.
Effect of doping.
Current Flow under
the influence of
electric field.
Behaviour at
Absolute 0K
temperature.
Bonding Types.
Comparison Chart of Conductor, Insulator and Semiconductor:
Comparison Chart Of Zener Breakdown And Avalanche Breakdown:
PARAMETERS
ZENER BREAKDOWN
Basic Definition
It occurs when the electric
field is created due to high
reverese voltage.
Less than 5 V
High Doping density
Exhibit Negative temperature
coefficient
Very Sharp
Reverse Voltage Range
Doping density
Temperature Coefficient
Nature of V-I Characteristics
Mechanism
Due to collision between
electrons
AVALANCHE
BREAKDOWN
It occurs when high velocity
electrons collide with
bounded electrons.
More than 5 V
Low doping density
Exhibit Positive temperature
coefficient
Not as sharp as Zener
Breakdown
Due to High electric field
Comparison chart of Diode and Zener Diode:
PARAMETERS
Definition
DIODE
Diode is a semiconductor
device which conducts only
in forward biased.
Operation in Reverse Biased
It gets damaged in reverse
biased.
ZENER DIODE
Zener diode is semiconductor
device which can conduct in
forward as well as reversed
biased.
It can operate without getting
damaged.
Circuit Symbol
Doping Intensity
In normal diodes doping
intensity is low.
Application
Diode is used in rectifiers,
clippers, clampers etc.
DIODE
PARAMETERS
In Zener diode doping
intensity is high to achieve
sharp breakdown.
Zener diode is mostly used in
voltage regulator.
ZENER DIODE
Comparison Chart of Diode and Transistor:
Parameter
Definition
Diode
A diode is a two terminal
device which allows current
to pass in one direction only.
Formation
It is formed by joining a Ptype semiconductor with Ntype semiconductor.
Transistor
Transistor is a three terminal
device which allows current
to flow from high resistance
region to low resistance
region
It is formed by sandwiching a
layer of P-type or N-type
material between two N-type
or P-type material on either
end.
Circuit Symbol
Depletion Layer
Number of Junctions
Terminals
Only one depletion region is
formed.
Only one junction between
P-type and N-type
semiconductor.
2 terminals are there in a
diode i.e. anode and cathode.
Two depletion region are
formed.
Two Junctions are formed
one in between emiter and
base and other between base
and collector.
3 terminals are there in
transistor i.e. emitter, base
and collector.
Considered as
Applications
It can be considered as a
switch.
Rectifier, voltage double,
clipper etc.
It can be considered as a
switch or an amplifier.
Amplifier, Oscillator etc.
Comparison Chart of NPN Transistor and PNP Transistor:
Parameter
Definition
Majority Charge Carriers
Circuit Symbol
Direction of Majority Charge
Carriers
Direction of Current
Direction of arrow in circuit
NPN TRANSISTOR
Transistor which consists of
one layer of P-type material
sandwiched between two
layers of N-type
semiconductor.
Electrons
PNP TRANSISTOR
Transistor which consists of
one layer of N-type material
sandwiched between two
layers of P-type
semiconductor.
Holes
Electrons flow from emitter
to collector.
Current flows from collector
to emitter.
Outwards from base
Holes flow from emitter to
collector.
Current flows emitter to
collector.
Inwards to base terminal.
symbol
Acts as
Mobility of Charge carriers
terminal.
It acts as current source as it
sources current from base
terminal of transistor.
Electrons possess high
mobiltiy thus conduction is
more
Commonly Used
NPN transistor is used in
most of the applications.
Frequency Response
Faster response than PNP
transistors.
It acts like current sink as it
completely sink the current
towards base terminal.
Holes are less mobile in
copmparison to electron thus,
PNP transistor provides less
condcution.
PNP transistor is less used in
comparison to NPN
transistor.
Slower frequency response.