BASIC ELECTRONICS

CONTENTS
• Resistor
• Capacitor
• Inductor
• Diode
• Transistor

Resistor
• A resistor is a two-terminal passive
electronic component. It is an electrical
component that limits or regulates the flow
of electrical current in an electronic circuit.
Resistors can also be used to provide a
specific voltage for an active device such
as a transistor.
• Symbol:

Conti…….
• S.I unit is ohm
• Symbol of ohm (Ω)
• Notation for resistance
O- for ohm
K- for kilo ohm
M- for mega ohm

Types of resistor
• Fixed type resistor
• Variable type resistor

Combination of resistor
• series combination
• parallel combination

Conti……
• Series combination

Conti….
• Parallel combination

CONTI….
• In series the current remains same
• In parallel the voltage remains same

Color coding table

Why we use resistor?
• Limiting of current
• Limiting of voltage
• Power dissipation

Capacitor

• A capacitor is a device for storing electric
charge
• A capacitor is a passive electronic component
consisting of a pair of conductors separated by
a dielectric (insulator).

CAPACITANCE
• This is a measure of a capacitor's ability to store charge.
• A large capacitance means that more charge can be stored.
• Capacitance can be measured using formula:
q = C V
where
C = capacitance,
q= charge,
V = potential difference.
• Unit of Capacitance is Farads(F).

Combination of capacitors
• Series combination
• Parallel combination

Series combination
• When capacitors are connected in series,
the capacitance decreases.
• In Series, total capacitance is given by the
formula:
1/Ct= 1/C1+1/C2+………

Parallel combination
• When capacitors are connected in parallel,
the capacitance increases.
• In Parallel, total capacitance is given by
the formula:
Ct= C1+ C2+………Cn

Types of capacitor
• Polarized capacitor
• Non polarized capacitor

Non Polarized capacitor
• The capacitor which do not have a polarity

Polarized capacitor
• The capacitor which have a polarity

Polarized Capacitors

Mica capacitor

Electrolytic capacitor

Paper Capacitor

Film Capacitor

Non-Polarized Capacitors

Electrolytic Capacitor (N.P)

Ceramic capacitor

Plastic capacitor

Features
• Capacitor offers low impedance to AC.
• It offers high impedance to DC.
• Reactance of capacitor is given by:
Xc =1/2π fc
where π =22/7

Applications
• Blocking DC Voltage
• Adjusting Frequency
• Use to generate a time delay application

Inductor

• The main characteristic of an inductor is its
ability to resist changes in current and store
energy in the form of a magnetic field.
• An inductor produces these magnetic fields
only when there is a current flowing through
an inductor

Inductance
• Inductance is the property of an inductor
• Inductance is the ability to oppose any change
in current which is flowing through an
inductor whether it be in magnitude or in
direction.
• It oppose rate of change of current
• Common symbol: (L)
• Unit of inductance is Henry (H)

Types of inductor
• Laminated core inductor
• Air core inductor
• Ferrite core inductor
• Toroidal core inductor
• Colour ring inductor/fixed inductor
• Wireless charging coil

Laminated Core Inductor

Air Core inductor

Ferrite Core Inductor

Toroidal Core Inductor

Colour ring inductor

Wireless Charging Coils

Features
• Changes electrical energy to magnetic energy
and stores it.
• Current flows to generate a magnetic field
• Dc can pass through but ac cannot pass
through at higher frequencies

Applications
• Used in transformer
• Sensor
• Radio frequency
• Energy storage
• Motors

Diodes

Diode
• Diode is an electronic component which
permits the flow of current in one direction
only.
• Today diodes are made up of
semiconductor material, therefore they are
often called semiconductor diodes or
crystal diodes.

Why we use it?
• Diodes are used for rectification.
• Diodes are used in electrical meters for
there protection.
• Diodes are used in wave shaping circuits.
• Diodes (LED) are used in display.

Material
• Diodes are semiconductor devices.
• Silicon(Si) or germanium(Ge) are used.

Types
• PN junction diode
• Zener Diode
• Light Emitting Diodes (LED)
• Photo Diodes

PN Junction Diode
• This diode is made by p-type & n-type
material.
• This PN junction diode works in forward
bias i.e. anode is connected to positive
terminal & cathode is connected to
negative terminal.

Symbol

How can we recognize?
• There is a silver band on the one side of
diode which is cathode (negative) terminal
of the diode & the other side is anode
(positive) terminal.

Zener Diode
• Zener Diode works in reverse bias.
• Symbol of zener diode:

How can we recognize zener a
diode?
• There is black band which is negative
terminal & other one is positive terminal.

Light Emitting Diode (LED)
• Light Emitting Diode (LED) operates in
forward bias.
• It emits light when connected in circuit.
• Symbol of LED:

How can we recognize LED?
• The shorter lead of the LED is negative
terminal & longer one is positive, also on
the negative terminal there is a flat spot
when we see from the top.

Photo Diode
• Often known as Photo detector.
• Photo Diode operates in reverse bias.
• Light falls on the PN junction of the photo diode which
creates electron-hole pair in the depletion layer which
causes flow of current.
• Current depends upon the light intensity
• When light incident on the photodiode then current flows
in the circuit.

Physical view of Photo diode:

Working of Photodiode
Photodiode

LDR(Light Dependent Resistor)
• A light dependent resistor is a semiconductor
electrical device that has a very high
resistance to the flow of electrical current in t
absence of light.
• When light strikes the device, it lowers its
resistance, allowing electrical current to flow
through it and on to other devices or electrical
circuits.

TRANSISTOR

TRANSISTOR
• A transistor is a semiconductor device used
to amplify and switch electronic signals. It is
made of a solid piece
of semiconductor material, with at least three
terminals for connection to an external circuit.
• Device with three terminals where one
terminal can be use to control the flow of
current through the other two terminals.

Conti….
• The three terminals are Emitter, Base and
Collector

Types of transistor
• Junction transistor
• Field effect transistor

Junction transistor
• Transistor are of two types:
1-> n-p-n
A straight switch
2-> p-n-p
A inverted switch

n-p-n as a switch
• When base of n-p-n is connected with
logic high voltage then it short circuit
emitter and collector (SWITCH ON).
• When base of n-p-n is connected with
logic low voltage then it open circuit both
emitter and collector (SWITCH OFF).

Circuit diagram to show a switching
RB
M
VCC
Logic 0
Logic 1
or
GND
Logic transistor Motor
0 off stop
1 on run

p-n-p as an inverted switch
• When base of p-n-p is connected with
logic high voltage then it open circuit
emitter and collector (SWITCH OFF).
• When base of p-n-p is connected with
logic low voltage then it short circuit both
emitter and collector (SWITCH ON).

Practically used
• As a switch
• As an amplifier
• For realizing logic gates

Relays
• Electro-mechanical switch
• A relay is an electrically operated switch
• Relays uses an electromagnet to operate a
switching mechanism mechanically
• Electromagnetic relay consists of a coil of wire
wrapped around a soft iron core, an iron yoke
which provides a low reluctance path for
magnetic flux, a movable iron armature, and
one or more sets of contacts

Buzzer
• An audio signaling device
• May be mechanical,
electromechanical,
or piezoelectric
• Typical uses of buzzers and beepers include
alarm devices, timers and confirmation of user
input such as a mouse click or keystroke
• Used as output device in alarm systems

Microphone
• Called as mic or mike
• An acoustic-to-electric transducer or sensor
• Converts sound into an electrical signal
• Used in applications such as
– Telephone
– tape recorders,
– karaoke systems,
– hearing aids,
– motion picture production,
– live and recorded audio engineering,
– television broadcasting
– computers for recording voice,
– speech recognition,
– non-acoustic purposes such as ultrasonic checking or
knock sensors

IC’S

• L293D
• 555
• LM358
• IC 7805(voltage controlled)

L293D IC
Vcc
EN1
EN2
12V

Truth table

Conti….
• L293D is a dual H-Bridge motor driver.
• So with one IC we can interface two DC motors
which can be controlled in both clockwise and
counter clockwise direction
• If you have motor with fix direction of motion
then you can make use of all the four I/Os to
connect up to four DC motors.
• L293D has output current of 600mA.
• Moreover for protection of circuit from back EMF
output diodes are included within the IC.

Interface motor with IC L293D
EN1
EN2
12V
VCC

555 IC

• The 555 Timer IC is an integrated circuit (chip)
used in a timer application, pulse generation
and oscillator applications.
• It works only on falling edge of the incoming
signal

Operating modes:
• It has three operating modes:
1) monostable
2) Bistable
3) Astable

Monostable mode
• In this mode, the IC has only one stable state
voltage
triggering pulse
output
time
voltage

Bistable mode
• In this mode, the IC has two stable state

Astable mode
• In this mode, the IC not having a single stable
state

LM358
• The LM358 IC consists of two independent
operational amplifiers which were designed
specifically to operate from a single power
supply over a wide range of voltages.
• It have two op-amp
• Single power supply

LM358 IC

Internal circuit

Features
• It have two op-amp
• Single power supply
• Supply range 3v-32v
• Eliminate need of dual supply

IC 7805
• It is a voltage regulator integrated circuit.
• It designed to automatically maintain a
constant voltage level
• It works on a negative feedback

IC 7805

Features
• Output current range up to 1A
• Output voltage 5V
• Input voltage range up to 12V
• Short circuit protection

THANKS :)