The document provides an introduction to electronic components, including their classification and examples of active components. It describes key active components like diodes, transistors, operational amplifiers (op-amps), and timers (IC-555) in detail. For diodes, it covers the light emitting diode (LED) and its working principle. For transistors, it explains NPN, PNP, JFET, and MOSFET types as well as their construction and working. It provides details on op-amp characteristics, applications, and uses in instrumentation amplifiers. It also describes the 555 timer and its uses in generating waveforms and applications like monostable multivibrators.
2. Electronic Component :
Electronic component is basic fundamental building block of any
electronic system precisely used to affect electrons and their
associated fields.
Each component may have one or more basic properties and it
behaves accordingly.
4. Active Components
Active components are those which conduct upon
providing some external energy i.e. require electrical
power to operate.
Usually they inject power into the circuit.
Examples – Diodes, Transister, ICs, Transformer etc.
5. DIODES
Diode is a one way valve for electricity.
It is a two terminal semiconductor device, these
two terminals are called the anode and cathode.
It lets the electricity to flow only in one direction.
6. Most diodes have painted line on one end showing
the direction or flow. The negative side is normally
white
Current flow through diode only when positive
voltage is applied to anode and negative voltage is
connected to cathode
If these voltages are reversed, then the current will
not flow.
9. LIGHT EMITTING DIODE (LED)
This is one of the most popular diodes used in our daily
life.
This is also a normal PN junction diode except instead
of silicone and germanium, the materials like gallium
arsenide, gallium arsenide phosphide used in
construction.
11. WORKING PRINCIPLE OF LED
Like a normal PN junction diode, this is connected in
forward bias condition so that the diode conducts.
The conduction takes place in a LED when the free
electrons in the conduction band combine with the
holes in the valence band. This process of
recombination emits light. This process is called
as Electroluminescence.
12. The color of the light emitted depends upon the gap
between the energy bands.
The materials used also effect the colors like, gallium
arsenide phosphide emits either red or yellow,
gallium phosphide emits either red or green and
gallium nitrate emits blue light. Whereas gallium
arsenide emits infrared light.
The LEDs for non-visible Infrared light are used
mostly in remote controls.
13. TRANSISTOR
A transistor is a 3 three terminal semiconductor
device in which a voltage is applied to one of the
terminal (called base) can control current that flows
across the other two terminals (called collector and
base).
These 3 terminals are called Emitter, Base and
Collector
14. It is a fundamental building block of circuitory in
mobile phones, computers, and several other
electronic devices.
Transistor has very fast response and is used in
number of functions including voltage regulations,
amplification, switching, oscillators etc.
Transistors may be packed individually or they can
be a part of an IC (integrated circuit).
Some of the ICs have billions of transistors ia very
small area.
15. TYPES OF
TRANSISTORS
NPN : When a P-type semiconductor is sandwitched
between two N-type semiconductor then it is called NPN.
Majority charge carriers are electrons.
PNP : When a N-type semiconductor is sandwitched
between two P-type semiconductor then it is called NPN.
Majority charge carriers are holes.
16. FIELD EFFECT TRANSISTORS
(FET)
The FET is a transistor that uses a electric field to
control the electrical behaviour of device.
FET
s are also known as unipolar transistors since they
involve single carrier type operation.
The device consist of an active channel through which
charge carriers, electrons or holes flow from source to
drain.
The conductivity of channel is function of potential
applied across the gate and source terminals.
17. FET’s 3 terminals are :
1. Source(S), through which the carriers enter the
channel. Conventionally, the current entering
the channel is designated by Is.
2. Drain(D), through which the carriers leave the channel.
Conventionally, the current entering
the drain is designated by ID. Drain to source voltage is
VDS.
3. Gate(G), the terminal that modulates the channel
conductivity. By applying voltage to G one can control
ID.
18. TYPES OF
FET
s
The JFET
: Junction field effect transistor
The MOSFET
: Metal oxide semiconductor
field effect transistor
The MNOS: Metal nitride oxide semiconductor
transistor
The DGMOSFET
: Dual gate MOSFET
The MODFET
: Modulation doped FET
The TFET
: Tunnel field effect Transistor etc.
19. MOSFET
MOSFET stands for Metal Oxide Silicon Field
Effect Transistor or Metal Oxide Semiconductor
Field Effect Transistor.
This is also called as IGFET meaning Insulated
Gate Field Effect Transistor.
The FET is operated in both depletion and
enhancement modes of operation.
20. The following figure shows how a practical MOSFET
looks like.
21. CONSTRUCTION OF MOSFET
The construction of a MOSFET is a bit similar to the
JFET
.
An oxide layer is deposited on the substrate to which
the gate terminal is connected. This oxide layer acts
as an insulator (sio2 insulates from the substrate),
and hence the MOSFET has another name as IGFET
(Insulated gate FET).
With negative gate bias voltage, it acts as depletion
MOSFET while with positive gate bias voltage it acts
as an Enhancement MOSFET.
23. The voltage at gate controls the operation of the
MOSFET
. In this case, both positive and negative
voltages can be applied on the gate as it is insulated
from the channel.
In the construction of MOSFET
, a lightly doped
substrate, is diffused with a heavily doped region.
Depending upon the substrate used, they are called
as P-type and N-type MOSFET
s.
24. CLASSIFICATION OF MOSFET
Depending upon the type of materials used in the
construction, and the type of operation, the MOSFET
s
are classified as in the following figure.
25. N-MOSFET
Let us consider an N-channel MOSFET to understand
its working. A lightly doped P-type substrate is taken
into which two heavily doped N-type regions are
diffused, which act as source and drain.
Between these two N+ regions, there occurs diffusion
to form an N-channel, connecting drain and source.
A thin layer of Silicon dioxide (SiO2) is grown over the
entire surface and holes are made to draw ohmic
contacts for drain and source terminals.
27. A conducting layer of aluminum is laid over the
entire channel, upon this SiO2layer from source to
drain which constitutes the gate.
The SiO2 substrate is connected to the common or
ground terminals.
Because of its construction, the MOSFET has a very
less chip area than BJT
, which is 5% of the
occupancy when compared to bipolar junction
transistor. This device can be operated in modes.
They are depletion and enhancement modes.
28. Working of N - Channel (depletion mode)
MOSFET
For now, we have an idea that there is no PN
junction present between gate and channel in this,
unlike a FET
.
29. together form a parallel plate capacitor.
get attracted and settle near SiO2 layer. But the
We can also observe that, the diffused channel N
(between two N+ regions), the insulating dielectric
SiO2 and the aluminum metal layer of the gate
If the NMOS has to be worked in depletion mode, the
gate terminal should be at negative potential while
drain is at positive potential.
When no voltage is applied between gate and source,
some current flows due to the voltage between drain
and source. Let some negative voltage
is applied at VGG. Then the minority carriers i.e. holes,
majority carriers, i.e., electrons get repelled.
30. With some amount of negative potential at VGG a
certain amount of drain current ID flows through
source to drain.
When this negative potential is further increased, the
electrons get depleted and the current ID decreases.
Hence the more negative the applied VGG, the lesser
the value of drain current ID will be.
The channel nearer to drain gets more depleted than
at source (like in FET) and the current flow decreases
due to this effect. Hence it is called as depletion
mode MOSFET
.
31. Working of N - Channel (Enhancement mode)
MOSFET
The same MOSFET can be worked in enhancement
mode, if we can change the polarities of the voltage
VGG. So, let us consider the MOSFET with gate
source voltage VGG being positive as shown in the
following figure.
32. carriers i.e. holes, get repelled and the majority carriers i.e.
of drain current ID flows through source to drain.
these are pushed further due to the voltage applied at VGG.
drain current ID will be.
When no voltage is applied between gate and source, some
current flows due to the voltage between drain and source.
Let some positive voltage is applied at VGG. Then the minority
electrons gets attracted towards the SiO2 layer.
With some amount of positive potential at VGG a certain amount
When this positive potential is further increased, the
current ID increases due to the flow of electrons from source and
Hence the more positive the applied VGG, the more the value of
The current flow gets enhanced due to the increase in electron
flow better than in depletion mode. Hence this mode is termed
as Enhanced Mode MOSFET.
33. Hence the more positive the applied VGG, the more
the value of drain current ID will be.
The current flow gets enhanced due to the increase
in electron flow better than in depletion mode. Hence
this mode is termed as Enhanced Mode MOSFET.
34. P-MOSFET
The construction and working of a PMOS is same
as NMOS. A lightly doped n-substrate is taken into
which two heavily doped P+ regions are diffused.
These two P+ regions act as source and drain. A
thin layer of SiO2 is grown over the surface.
Holes are cut through this layer to make contacts
with P+ regions, as shown in the following figure.
36. DRAIN CHARACTERSTICS
The drain characteristics of a MOSFET are drawn
between the drain current ID and the drain source
voltage VDS. The characteristic curve is as shown below
for different values of inputs.
37. TRANSFER CHARACTERSTICS
Transfer characteristics define the change in the value
of VDS with the change in ID and VGS in both depletion
and enhancement modes. The below transfer
characteristic curve is drawn for drain current versus
gate to source voltage.
38. -
Noninverting
OP-AMP (IC-741)
An operational amplifier is a direct-coupled high-gain
amplifier.
It offers the gain of the order of 106.
+VCC
Inverting
input
Op-Amp output
IC-741
+
input
-VEE
39. circuit package.
excitation/input, 1 pin is not used hence named IC-741.
and followed by a level translator and an output stage.
An operational amplifier is available as a single integrated
There are 8 pins in it, 7 pins are active, 4 pins are for
It usually consisting of one or more differential amplifiers
It is a versatile device that an amplify DC as well as AC.
PIN DIAGRAM
40. IDEAL OP-AMP CHARACTERSTICS
Infinite voltage gain.
Infinite input resistance so that almost any signal
source can drive it and there is no loading on the
preceding stage.
Zero output resistance so that output can drive an
infinite number of other devices.
Infinite bandwidth so that any frequency signal from 0
to ∞ Hz can be amplified without attenuation.
Infinite CMRR so that the output common-mode noise
voltage is zero.
Infinite slew rate so that output voltage changes occur
simultaneously with input voltage changes.
41. Equivalent Circuit of Op-Amp
Vo =Ad (V1-V2) = AdVd
The op-amp amplifies the difference between the two
input voltages. It does not amplify the input voltages
themselves.
The polarity of the output voltage depends on the polarity
of the difference voltage Vd.
43. O/P
LEVEL
Internal Circuit Of Op-Amp
NON
INVERTING I/P
INPUT INTERMEDIAT SHIFTING OUTPUT
STAGE E STAGE STAGE
INVERTING I/P STAGE
DUAL I/P DUAL I/P EMITTER DUAL I/P
BALANCED O/P UNBALANCED FOLLOWER CIRCUIT BALANCED O/P
DIFFERENTIAL O/P USING CONSTANT DIFFERENTIAL
AMPLIFIER DIFFERENTIAL CURRENT SOURCE AMPLIFIER
AMPLIFIER
44. amplifier. This stage generally provides most of
resistance of the op-amp.
the voltage
amplifier, which is driven by the output of the first stage. On
unbalanced output.
the intermediate stage is well above ground potential.
the intermediate stage downwards to zero volts with respect
symmetry amplifier output stage. The output stage increases
capabilities of the op-amp.
resistance.
Continued....
The input stage is the dual input balanced output differential
gain of the amplifier and also establishes the input
The intermediate stage is usually another differential
most amplifiers, the intermediate stage is dual input,
Because of direct coupling, the dc voltage at the output of
Therefore, the level translator (shifting) circuit is used after
to ground.
The final stage is usually a push pull complementary
the Voltage swing and raises the ground supplying
A well designed Output stage also provides low output
45. APPLICATIONS
It was originally designed for computing such
mathematical functions as addition, subtraction,
multiplication, and integration.
Thus the name operational amplifier stems from its
original use for these mathematical operations and is
abbreviated to op-amp.
With the addition of suitable external feedback
components, the modern day op-amp can be used for a
variety of applications, such as ac and dc signal
amplification, active filters, oscillators, comparators,
regulators, and others.
46. For e.g. measurements of temperature and humidity inside
Its one of the important application is in construction of
instrumentation amplifier.
INSTRUMENTATION
AMPLIFIER
In many industrial and consumer applications the
measurement and control of physical conditions are very
important.
For e.g. measurements of temperature and humidity insi
a dairy or meat plant permit the operator to make
necessary adjustments to maintain product quality.
Similarly, precise temperature control of plastic furnace is
needed to produce a particular type of plastic.
49. Continued…
Some transducers produce outputs with sufficient
strength to perform their use directly, many do not.
T
o amplify the low-level output signal of the transducer
so that it can drive the indicator or display is the major
function of the instrumentation amplifier.
The instrumentation amplifier is intended for precise,
low-level signal amplification where low noise, low
thermal and time drifts, high input resistance, and
accurate closed-loop gain are required. Besides, low
power consumption, high common-mode rejection ratio,
and high slew rate are desirable for superior
performance.
50. TIMER (IC-555)
IC 555 was Introduced in 1970 by SIGNATICS
corporation.
It is used for generation of square wave (asymmetric and
symmetric), saw tooth, and various other applications
such as Astable, Monostable, and Bistable multivibrator.
The most versatile linear integrated circuits is the 555
timer.
51. accurate and highly stable time delays or oscillation.
DIP
.
as monostable (one-shot) multivibrator or as an astable (free
on +5 to + 18 V supply voltage in both free-running (astable)
cycle; timing is from microseconds through hours; it has a
astable multivibrators, dc-dc converters, digital logic probes,
tachometers, temperature measurement and control, infrared
electric eyes, and many others.
The 555 is a monolithic timing circuit that can produce
The device is available as an 8-pin metal can, an 8-pin mini
The timer basically operates in one of the two modes: either
running) multivibrator.
The important features of the 555 timer are these: it operates
and one- shot (monostable) modes; it has an adjustable duty
high current output; it can source or sink 200 mA.
A sample of these applications includes mono-stable and
waveform generators, analog frequency meters and
transmitters, burglar and toxic gas alarms, voltage regulators,
54. PIN DESCRIPTION AND
WORKING
Pin 1: Ground
All voltages are measured with respect to this terminal.
Pin 2: Trigger
The output of the timer depends on the amplitude of the
external trigger pulse applied to this pin. The output is
low if the voltage at this pin is greater than 2/3 VCC.
However, when a negative-going pulse of amplitude
larger than 1/3 VCC is applied to this pin, the
comparator 2 output goes low, which in turn switches
the output of the timer high. The output remains high as
long as the trigger terminal is held at a low voltage.
55. Pin 3: Output
There are two ways a load can be connected to the output
terminal: either between pin 3 and ground (pin 1) or between
pin 3 and supply voltage +VCC (pin 8). When the output is low,
the load current flows through the load connected between
pin 3 and +VCC into the terminal and is called the sink current.
However, the current through the grounded load is zero when
the output is low. For this reason, the load connected between
pin 3 and +VCC is called the normally on load and that
connected between pin 3 and ground is called the normally off
load. On the other hand, when the output is high, the current
through the load connected between pin 3and + VCC
(normally on load) is zero. However, the output terminal
supplies current to the normally off load. This current is called
the source current. The maximum value of sink or source
current is 200 mA.
56. Pin 4: Reset.
The 555 timer can be reset (disabled) by applying a
negative pulse to this pin. When the reset function is not
in use, the reset terminal should be connected to + VCC
to avoid any possibility of false triggering.
Pin 5: Control voltage
An external voltage applied to this terminal changes the
threshold as well as the trigger voltage . In other words,
by imposing a voltage on this pin or by connecting a pot
between this pin and ground, the pulse width of the
output waveform can be varied. When not used, the
control pin should be bypassed to ground with a 0.01-μF
capacitor to prevent any
noise problems.
57. Pin 6: Threshold
This is the non-inverting input terminal of comparator 1, which
monitors the voltage across the external capacitor. When the
voltage at this pin is threshold voltage 2/3 V, the output of
comparator 1 goes high, which in turn switches the output of
the timer low.
Pin 7: Discharge
This pin is connected internally to the collector of transistor,
When the output is high, Transistor is off and acts as an open
circuit to the external capacitor C connected across it. On the
other hand, when the output is low, Q1 is saturated and acts
as a short circuit, shorting out the external capacitor C to
ground.
Pin 8: + VCC
The supply voltage of +5 V to +18 is applied to this pin with
respect to ground (pin 1).
59. Passive Components
Passive electronic components are those that
don’t have the ability to control current by
means of another signal.
They start their operation once they are
connected.
No external energy is needed for their
operation.
E.g. Resistors, capacitors, inductors, LDR etc.
60. RESISTOR
It is device that resists the flow of current.
Resistors comes in variety of resistance values(how
much they resist current, measured in unit called
ohm) and power rating (how much power they can
handle without burning up, measured in watts).
62. POTENTIOMETER
A potentiometer is a 3 terminal resistor with a sliding
or rotating contact that forms an adjustable voltage
divider.
If only two terminals are used, one end and the
wiper, it act as a variable resistor
63. LIGHT DEPENDENT RESISTOR
(LDR)
An LDR is a component that has a (variable)
resistance that change with the light intensity
that falls upon it.
This allows them to be used in light sensing
circuits.
64. CAPACITOR
It is a device that can temporarily store an electric
charge.
Capacitors come in several varieties, the two most
common being ceramic disk and electrolyte.
The amount of capacitance of a given capacitor is
usually measured in micro farads, uf.
65. INDUCTOR
An inductor is also called a coil, choke, or
reactor, is a passive two terminal electrical
component that stores energy in form of
magnetic field when electric current flows
through it.
An inductor typically consists of an insulated
wire wound into a coil around a core.
67. LOGIC GATES
Logic gates are the basic building blocks of any digital
system.
It is an electronic circuit having one or more than one
input and only one output.
At any given moment, every terminal is in one of the
two binary conditions low (0) or high (1), represented
by different voltage levels.
The relationship between the input and the output is
based on a certain logic.
Based on this, There are 7 different logic gates : AND,
OR, NOT
, NAND, NOR, XOR, XNOR etc.
68.
69. uth table:
AND GATE
A circuit which performs an AND operation is shown in
figure. It has n input (n >= 2) and one output.
Logic diagram:
Tr
70. OR GATE
A circuit which performs an OR operation is shown in
figure. It has n input (n >= 2) and one output.
Logic diagram:
Truth table:
71. NOT GATE
NOT gate is also known as Inverter. It has one input
A and one output Y
.
Logic diagram:
Truth table:
72. NAND GATE
A NOT-AND operation is known as NAND operation. It
has n input (n >= 2) and one output.
Logic diagram:
Truth table:
73. NOR GATE
A NOT-OR operation is known as NOR operation. It
has n input (n >= 2) and one output.
Logic diagram:
Truth table:
74. Truth table:
XOR
GATE
XOR or Ex-OR or exclusive-OR gate is a special type
of gate. It can be used in the half adder, full adder and
subtractor. It has n input (n >= 2) and one output.
Logic diagram:
75. XNOR
GATE
XNOR or EX- NOR or exclusive-NOR gate is a
special type of gate. It can be used in the half adder,
full adder and subtractor. It has n input
(n >= 2) and one output.
Logic diagram:
Truth table:
76. DC TO DC BOOSTER CIRCUIT OR
BOOST CONVERTER
A process that changes one DC voltage to a
different DC voltage is called DC to DC conversion.
A boost converter is a DC to DC converter with
output voltage greater than the source voltage.
A boost converter is sometimes called step-up
converter since it “steps-up” the source voltage.
DC to DC boosters are available as ICs requiring
few more components and are also available as
complete hybrid circuit modules, ready for use with
in a electronic assembly.
