This project we made for our Workshop 2 in 6 semester of our engineering. This project is made by students of Electronics And Communication Branch. Hope it will help other students.

1. Audio Amplification System
A Workshop-II Report
Submitted in partial fulfillment of the requirement for the award of Degree of Bachelor
of Engineering in Electronics & Communication
Submitted to
RAJIV GANDHI PROUDYOGIKI VISHWAVIDHYALAYA
BHOPAL (M.P.)
WORKSHOP-II REPORT
Submitted By:
Saransh Tiwari (0176EC161070) Shashwat Pratap(0176EC161073)
Shivam Sharma(0176EC161075) Anshul Suryawanshi(0176EC161016)
DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING
LAKSHMI NARAIN COLLEGE OF TECHNOLOGY
EXCELLENCE, BHOPAL
Session 2018-19

2. LAKSHMI NARAIN COLLEGE OF TECHNOLOGY
EXCELLENCE, BHOPAL
Department of Electronics & Communication Engineering
CERTIFICATE
This is to certify that the work embodied in this Workshop-2 title “Audio
Amplification System” has been satisfactorily completed by Saransh
Tiwari, Shashwat Pratap, Shivam Sharma and Anshul Suryawanshi,
students of Third year. It is a bonafide piece of work, carried out under my
supervision and guidance in the Department of Electronics &
Communication Engineering, Lakshmi Narain College of Technology
Excellence, Bhopal, for partial fulfillment of the Bachelor of Engineering
during the academic year 2018-19.
Under the Supervision of
_____________________
Project Co-ordinator
Dr. Shivi Chaturvedi
____________________
Project Co-ordinator
Prof. Abhinav Bhargava
Approved By
____________________
Dr. Mukul Shrivastava
Head of the Department

3. LAKSHMI NARAIN COLLEGE OF TECHNOLOGY
EXCELLENCE, BHOPAL
Department of Electronics & Communication Engineering
DECLARATION
We, Saransh Tiwari, Shashwat Pratap, Shivam Sharma and Anshul
Suryawanshi, students of Bachelor of Engineering, Electronics &
Communication Engineering, Lakshmi Narain College of Technology,
Bhopal, here by declare that the work presented in this Workshop-2 Project
is outcome of our own work, is bonafide, correct to the best of our
knowledge and this work has been carried out taking care of Engineering
Ethics. The work presented does not infringe any patented work and has not
been submitted to any University for the award of any degree or any
professional diploma.
____________ _____________
Saransh Tiwari Shashwat Pratap
Enrollment No. 0176EC161070 Enrollment No. 0176EC161073
____________ _____________
Shivam Sharma Anshul Suryawanshi
Enrollment No. 0176EC161075 Enrollment No. 0176EC161016
Date: ___-___-_____
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4. ACKNOWLEDGEMENT
Reasons can be given & they can be many but nothing can replace the
efforts of numerous people behind the work, put in by the creator, giving us
constant support all the way. On the very outset I would like to thank
Dr. V. K. Sahu, Principal, LNCTE, Bhopal for providing me the glorious
opportunity to work on this project. I express my hearty gratitude to
Dr. Mukul Shrivastava, Head of Department Electronics &
Communication Engineering. His invaluable guidance, advice & time out
of extremely busy schedule made this work an enthusiastic experience. I
wish to express my most sincere gratitude for her whole hearted
cooperation.
I am grateful, beyond my sense of gratitude, to
Dr. Shivi Chaturvedi and Prof. Abhinav Bhargava Project Coordinator,
Department of Electronics & Communication Engineering, for her kind
cooperation throughout the planning & preparation of this project. Working
on this project was quite a wonderful experience & that too an unforgettable
one. Without his unhindered support, sustained interest, unlimited patience,
sound counsel & tremendous knowledge in the field of electronics, this
work would have not been possible.
Nothing can be taken away from my project guide
Dr. Shivi Chaturvedi and Prof. Abhinav Bhargava Department of
Electronics & Communication Engineering, who has been instrumental in
guiding us through the various aspects of designing of our project &
implementing the idea of the project “Audio Amplification System”.
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5. TABLE OF CONTENTS
TOPIC NAME PAGE NUMBER
Certificate
Declaration i
Acknowledgement ii
Table of Content iii
List of Figures iv
List of Tables v
Abstract vi
Chapter 1: Introduction (1-2)
Chapter 2: Working (3-5)
Chapter 3: Main Components (6-14)
3.1 Audio Source (DAC) 7-8
3.2 Audio Jack 9
3.3 LM 386 IC 10-11
3.4 Transistor 11
3.5 7805CV Voltage Converter 12
3.6 Loudspeaker 13
3.7 Single Layer PCB 14
Chapter 4: Circuit Diagram (15-17)
4.1 Circuit Diagram 16
Chapter 5: Advantages (18-19)
Chapter 6: Applications (20-21)
Chapter 7: Conclusion (22-23)
Chapter 8: Future Scope (24-25)
Reference
iii

6. ABSTRACT
This project focuses on the control of audio power amplifiers. Is the
development and implementation of a system of controlled cooling and
optimizing the power consumption and temperature generated, using an
advanced control algorithm. The approach is based on the configurations of
integrated circuits (IC) audio amplifiers allowing us to obtain data energy
consumption and parameters of temperature gradient, generally with the
required parameters will be processed by a microcontroller (uC) to pass to
run programmed by a control algorithm(PID) instructions. The frequency at
which works is 20Hz to 20kHz with 75dB decibel maximum. Finally both
analysis and theoretical control simulation showed that the use of a good
control configuration based on energy regulation and switching amplifiers
allows the temperature was controlling with excellent accuracy and reduces
wear on stage of electronic circuit.
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7. LIST OF FIGURES
Topic Name Page No.
2.1 Block Diagram of Working 4
3.1 Working of DAC 7
3.2 8-bit DAC 8
3.3 Audio Jack 9
3.4 LM 386 IC 10
3.5 Transistor 11
3.6 7805CV Voltage Converter 12
3.7 Loudspeaker 13
3.8 Single Layer PCB 14
4.1 Circuit Diagram 16
v

8. LIST OF TABLES
Topic Name Page No.
3.1 Pin Discription of 7805CV 12
iv

9. CHAPTER 1
1

10. INTRODUCTION
Currently in the audio amplifiers be perceived the need an efficient
moderate sound control and good cooling system, either in various
configurations amplification circuits. Often used this ventilation system.
Focused on generating gain and amplifying the incoming signal to be then
sent to the output load, thereby leaving out the cooling control system, and
especially the required consumption of each stage. Thereby causing severe
problems in integrated circuit devices and power because the temperature
generated by them. Therefore it is possible to control said temperature
generated and directly proportional current consumption. Thus, it becomes
absolutely necessary to have an automated system that monitors each stage,
from the detection to amplification stage. Using data obtained mainly from
the sensors and integrated circuits. It is therefore necessary to be able to
identify parameters of possible short circuits and wrong power settings,
these walls will be able to isolate the supply of each stage. Therefore, to
accomplish this task control and identification is essential to have an
algorithm that this widespread with each stage of the design is done through
a hardware that has the necessary pattern recognition algorithms. Also, In
other words this project focuses on minimizing consumption and optimize
control by providing an alternative solution for easy access.
2

11. CHAPTER 2
3

12. WORKING
Fig 2.1 Block Diagram of Working
Circuit diagram of the LM386 based audio amplifier. It is built around
popular amplifier LM386 (IC1), an 8-ohm, one-watt speaker (LS1), four
capacitors and a few other components. A 6V battery is used to power this
project. Four electrolytic capacitors [two 10µF, 16V (C1 and C2) and two
220µF, 16V (C3 and C4)] are used in this circuit. C1 is connected to the
middle terminal of 10k potentiometer VR1. C2 is connected to pins 1 and 8
of IC1. Pin 5 of IC1 is its output terminal, which is connected to speaker
LS1 through C3. C4 is connected to the positive terminal of 6V battery and
ground. Positive side of 6V is connected to pin 6 of IC1 and the other side
to ground terminal.
4

13. Output of audio amplifier LM386 is 1 watt, while its voltage gain is 20 to
200. The circuit consists of a transmitter and a receiver. Both the transmitter
and the receiver are built around IC LM386, powered by a 9V battery.
A single-side PCB for LM386 amplifier is shown in Fig. 3 and its
component layout in Fig. 4. After assembling the circuit on a PCB, enclose
it in a suitable box. Fix connector CON1 on the front panel for input and
loudspeaker LS1 at the rear side of the box. Connect VR1 on the front panel
for controlling the volume.
5

14. CHAPTER 3
6

15. Main Components
3.1 Audio Source (DAC) :-
Digital to Analog Converter (DAC) is a device that converts Digital audio
signal to Analog audio signal. A DAC takes digital data and transforms it
into an analog audio signal. Afterward, it sends that analog signal to an
amplifier. When you hear digital recordings, you’re actually listening to an
analog signal that was converted from digital by a DAC.
Fig 3.1 Working of DAC
There are several DAC architectures; the suitability of a DAC for a
particular application is determined by figures of
merit including: resolution, maximum sampling frequency and others.
Digital-to-analog conversion can degrade a signal, so a DAC should be
specified that has insignificant errors in terms of the application.
DACs are commonly used in music players to convert digital data streams
into analog audio signals. They are also used in televisions and mobile
phones to convert digital video data into analog video signals.
7

16. These two applications use DACs at opposite ends of the
frequency/resolution trade-off. The audio DAC is a low-frequency, high-
resolution type while the video DAC is a high-frequency low- to medium-
resolution type.
Fig 3.2 8-bit DAC
An ideal DAC converts the abstract numbers into a conceptual sequence
of impulses that are then processed by a reconstruction filter using some
form of interpolation to fill in data between the impulses. A
conventional practical DAC converts the numbers into a piecewise constant
function made up of a sequence of rectangular functions that is modeled
with the zero-order hold. Other DAC methods (such as those based on delta-
sigma modulation) produce a pulse-density modulated output that can be
similarly filtered to produce a smoothly varying signal.
Due to the complexity and the need for precisely matched components, all
but the most specialized DACs are implemented as integrated circuits (ICs).
Discrete DACs would typically be extremely high speed low resolution
power hungry types, as used in military radar systems.
8

17. 3.2 Audio Jack :-
Fig 3.3 Audio Jack
A socket for plugging in an audio source. Audio jacks are found on many
types of audio equipment and musical instruments that accept external
sound sources. In a car or truck, an audio jack, also called a "media jack" or
"auxiliary (AUX) jack," is a mini-phone socket that connects any portable
music player to the vehicle's amplifier and speakers. One end of a mini-
phone cable plugs into the headphones socket of any CD, tape cassette or
digital music player, and the other end plugs into the car's audio jack.
Audio jacks have been around for decades and have been used in a wide
variety of applications. While simple in their basic functionality, they can be
used in complex systems. To better understand some of their capabilities,
we will dig into the "guts" of these connectors and see what they
connections. In this post, we are going to look at how to read these
schematics, describe the various switch types available, and discuss how
they are implemented in audio applications.
9

18. 3.3 LM386 IC :-
The IC LM386 is a low-power audio amplifier, and it utilizes low power
supply like batteries in electrical and electronic circuits. This IC is available
in the package of mini 8-pin DIP. The voltage gain of this amplifier can be
adjusted to 20, and the voltage gain will be enhanced to 200 by external
components like resistors as well as capacitors among the pins 1 & 8. When
this amplifier uses a 6V power supply for the operation then the static power
drain will be 24 milliwatts to make the amplifier for an ultimate operation of
the battery. This amplifier consists of 8-pins where pin-1 and pin-8 are gain
control pins of the amplifier, and this IC is most widely used IC that allows
a customer to increase volume.
Fig 3.4 LM386 IC
 Pin1 (Ga+-gain Pin): Pin-1 is gain pin, used adjust the amplifier gain by
connecting this IC to an external component capacitor.
 Pin2 (+IN-Non-inverting): Pin-2 is the non-inverting pin, is used to
provide the audio signal.
 Pin3 (+IN): Pin-3 is the inverting terminal and it is normally connected to
ground.
 Pin4 (GND): Pin-4 is a ground pin connected to the ground terminal of the
system
 Pin5 (Vout): Pin-5 is the output pin, used to provide amplified output
audio, and allied to the speaker.
10

19.  Pin-6 (VCC or VSS): Pin-6 is connected to the power
 Pin-7 (Bypass): Pin-7 bypass pin is used to connect a decoupling capacitor.
 Pin-8 (Gain): Pin-8 is the gain setting pin.
3.4 Transistor :-
Fig 3.5 Transistor
A transistor is a device that regulates current or voltage flow and acts as a
switch or gate for electronic signals. Transistors consist of three layers of a
semiconductor material, each capable of carrying a current. Transistors are
created through a chemical process known as doping, where the
semiconductive material either gains an extra negative charge (N-type) or
extra positive charge (P-type). There are two configurations for this, either
PNP or NPN with the middle material acting as the base or flow control.
Transistors are the basic elements in integrated circuits (IC), which consist
of very large numbers of transistors interconnected with circuitry and
baked into a single silicon microchip.
11

20. 3.5 7805CV Voltage Converter :-
Fig 3.6 7805CV Voltage Converter
Voltage sources in a circuit may have fluctuations resulting in not
providing fixed voltage outputs. A voltage regulator IC maintains the
output voltage at a constant value. 7805 IC, a member of 78xx series of
fixed linear voltage regulators used to maintain such fluctuations, is a
popular voltage regulator integrated circuit (IC). The xx in 78xx indicates
the output voltage it provides. 7805 IC provides +5 volts regulated power
supply with provisions to add a heat sink.
Table 3.1 Pinout of 7805CV
Pin
No.
Pin Function Description
1 INPUT
Input voltage (7V-
35V)
In this pin of the IC positive
unregulated voltage is
given in regulation.
2 GROUND Ground (0V)
In this pin where the
ground is given. This pin is
neutral for equally the input
and output.
3 OUTPUT
Regulated output; 5V
(4.8V-5.2V)
The output of the regulated
5V volt is taken out at this
pin of the IC regulator.
12

21. 3.6 Speaker :-
A loudspeaker is an electroacoustic transducer a device which converts an
electrical audio signal into a corresponding sound.The most widely used
type of speaker in the 2010s is the dynamic speaker, invented in 1925
by Edward W. Kelloggand Chester W. Rice. The dynamic speaker operates
on the same basic principle as a dynamic microphone.
Fig 3.7 Loudspeaker
Loudspeakers are typically housed in a speaker enclosure or speaker cabinet
which is often a rectangular or square box made of wood or sometimes
plastic. The enclosure's materials and design play an important role in the
quality of the sound. Where high fidelity reproduction of sound is required,
multiple loudspeaker transducers are often mounted in the same enclosure,
each reproducing a part of the audible frequency range.
13

22. 3.7 Single Layer PCB (Printed Circuit Board) :-
Fig 3.8 Single Layer PCB
It is one that is made out of a single layer of base material or substrate.
One side of the base material is coated with a thin layer of metal. Copper
is the most common coating due to how well it functions as an electrical
conductor. Once the copper base plating is applied, a protective solder
mask is usually applied, followed by the last silk-screen to mark out all of
the elements on the board. Surface mount PCBs don't utilize wires as
connectors. Instead, many small leads are soldered directly to the board,
meaning that the board itself is used as a wiring surface for the different
components. This allows circuits to be completed using less space, freeing
up space to allow the board to complete more functions, usually at higher
speeds and a lighter weight than a through-hole board would allow.
14

23. CHAPTER 4
15

24. CIRCUIT DIAGRAM
4.1 Circuit Diagram -
Fig 4.1 Ckt Diagram
Usually, the audio output from a laptop’s built-in speakers is low. A power
amplifier is required to get a high volume. Here is a simple circuit to
amplify the laptop’s audio output. The circuit is built around power
amplifierand a few other components. Dual channel audio power amplifier.
It has low distortion over a wide range of low to high frequencies with good
channel separation. Inbuilt dual channels enable it for stereo and bridge
amplifier applications. In dual mode gives 6 watts per channel and in
bridge mode 19- watt output. It has ripple rejection of 46 dB. The audio
effect can be realised by using two 6-watt speakers. Connect pins 2, 6 and
ground of IC1 to the stereo jack which is to be used with the laptop.
Assemble the circuit on a general-purpose PCB and enclose in a suitable
16

25. cabinet. The circuit works off regulated 12V power supply. It is
recommended to use audio input socket in the circuit board. Use a proper
heat-sink . By varying the voltage applied or tone/volume control in Laptop,
the volume of the amplifier can be varied.
A single-side PCB for LM386 amplifier is shown in Fig. 3 and its
component layout in Fig. 4. After assembling the circuit on a PCB, enclose
it in a suitable box. Fix connector CON1 on the front panel for input and
loudspeaker LS1 at the rear side of the box. Connect VR1 on the front panel
for controlling the volume. Inverting pin 2 of IC1 is connected to ground
and non-inverting pin 3 is connected to the input terminal through VR1.
Audio input is fed to CON1. VR1 is used to control volume.
Construction and testing. Circuit diagram of the LM386 based audio
amplifier is shown in Fig. 2. It is built around popular amplifier LM386
(IC1), an 8-ohm, one-watt speaker (LS1), four capacitors and a few other
components. A 6V battery is used to power this project. Four electrolytic
capacitors [two 10µF, 16V (C1 and C2) and two 220µF, 16V (C3 and C4)]
are used in this circuit. C1 is connected to the middle terminal of 10k
potmeter VR1. C2 is connected to pins 1 and 8 of IC1. Pin 5 of IC1 is its
output terminal, which is connected to speaker LS1 through C3. C4 is
connected to the positive terminal of 6V battery and ground. Positive side of
6V is connected to pin 6 of IC1 and the other side to ground terminal to pin
4. Inverting pin 2 of IC1 is connected to ground and non-inverting pin 3 is
connected to the input terminal through VR1. Audio input is fed to CON1
VR1 is used to control volume.
17

26. CHAPTER 5
18

27. ADVANTAGES
This is a low power amplifier according to its amplification factor it has
some advantages as follows :-
 This circuit of this amplifier is no so complex so it is easy to make it.
 This amplifier circuit uses capacitor and resistor and an IC due to this
the cost is very low.
 By doing the proper matching of impedance a medium output can
obtained.
 The reliability of this audio amplifier is also high.
 It provides low amplitude distortion.
 It provides high audio fidelity.
 It has low amplitude distortion.
19

28. CHAPTER 6
20

29. APPLICATIONS
 The level of output is not that much high. To obtain high output
multistage may be required.
 The quality of sound is also low.
 There is some amount of noise present in the final output.
 It can be used in public address systems.
 It can be used in theatrical and concert sound reinforcement systems.
 It can be used in domestic systems such as a stereo or home-theatre
system.
 It can also be used as a guitar amplifiers and electric keyboard
amplifiers.
21

30. CHAPTER 7
22

31. Conclusion
The amplifier design revealed to be a major challenge, being an excellent
source of knowledge for acquiring an extended background on analog and
digital electronics. Considering the multiple variables that may influence the
performance of the analog audio-amplifier, all major goals were
accomplished. An integrated valve amplifier with excellent characteristics
has resulted. In part credit should be given to available electric simulators
that allowed a much easier optimization procedure. The digital part was
delineated and implemented with success, bringing a very comfortable
mean of adjustment to an excellent sounding amplifier, while the user is
listening and appreciating a good sound experience. The user does not need
to worry about biasing the valves as they age with use. Moreover, it may
serve as an alert system for possible destructive damages, preventing major
harms to the amplifier by warning the user for the need of substituting the
defective devices.
23

32. CHAPTER 8
24

33. Future scope
While working the dissertation, some gaps were detected in the area of
valve amplifiers that could be further investigated. Judging by the
experience obtained from this work, the existent triode valve SPICE models
have a good degree of accuracy, but pentode models can probably be
improved. Still, the biggest deficit in simulation models, in the context of
valves circuits, is the output transformer. In fact, after quite a searching,
simulation with the use of output models is very unusual within the valve
amplifier designer realm. Very few models are available and probably, if
research was made around this subject, good models for these devices
would become popular both to transformer and amplifier designers.
25

34. Reference
https://paginas.fe.up.pt/~ee05202/conclusion.html
https://electronicsforu.com/electronics-projects/lm386basedaudioamplifier
https://en.wikipedia.org/wiki/Audio_power_amplifier
https://www.academia.edu/6736968/Audio_Amplifier_Design_Project
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