(Tiểu Luận) Electronic Engineering Audio Amplifier Circuit.docx

DA NANG UNIVERSITY VIETNAM – KOREA UNIVERSITY OF INFORMATION AND COMMUNICATION TECHNOLOGY ELECTRONIC ENGINEERING AUDIO AMPLIFIER CIRCUIT Student made TRAN KHANH DUY DANG ANH CUONG Instructor DR NGUYEN[.]

DA NANG UNIVERSITY VIETNAM – KOREA UNIVERSITY OF INFORMATION AND COMMUNICATION TECHNOLOGY

ELECTRONIC ENGINEERING

AUDIO AMPLIFIER CIRCUIT

Student made: TRAN KHANH DUY

DANG ANH CUONG

Da nang, May 2023

DA NANG UNIVERSITY VIETNAM – KOREA UNIVERSITY OF INFORMATION AND COMMUNICATION TECHNOLOGY

ELECTRONIC ENGINEERING

AUDIO AMPLIFIER CIRCUIT

Da nang, May 2023

INSTRUCTOR’S COMMENTS

Da nang, May 2023

Lectures

DR Nguyen Vu Anh Quang

THANK YOU

First of all, we would like to thank Vietnam - Korea University of Information and Communication Technology for always listening and always creating the best learning conditions for us and all students in the school Next, we would like to express our deepest gratitude to our guide Dr Nguyen Vu Anh Quang has enthusiastically helped and found many of my mistakes in the process of researching and researching The teacher also guided us a lot to complete the end-of-term exercises.

Because of the limited time, my understanding level is still limited Therefore, in the end of the lesson, to avoid mistakes, I hope to receive the comments of the teachers to make our product exercises more complete.

Da nang, May 2023

Student made

Dang Anh Cuong Tran Khanh Duy

TABLE OF CONTENTS

INSTRUCTOR’S COMMENTS 3

THANK YOU 3

CHAPTER I: REASON FOR SELECTION AND ANALYSIS OF THE TOPIC 3 2 Analyze the topic 3

2.1 System requirements 3

2.2 Function of the circuit 3

CHAPTER II : BLOCK DIAGRAM 4

CHAPTER III: CHARACTERISTICS AND CALCULATION OF CIRCUIT SPECIFICATIONS ONLY 5

1 Principle diagram 5

2 Circuit parameter calculation 6

2.1 One-way mode 6

2.2 Alternating mode 7

CHAPTER IV: CIRCUIT SIMULATION AND TESTING 8

1 Parts list 8

2 Simulation circuit 9

CHAPTER V: CONCLUDE 10

2

CHAPTER I: REASON FOR SELECTION AND ANALYSIS OF THE TOPIC

1 Reason for choosing the topic

The economy is increasingly internationalized, and the society is also developing

To meet the urgent needs of life and integrate with the development progress

in the world, today's scientific and technical disciplines must be improved and developed in terms of quality and wide applicability In which, the computer technology industry also plays an important role in the world's daily life as well as in production As a student still sitting at school, I have been trained in specialized knowledge of the field Although I have learned and practiced a lot in class, it is only a small part compared to the outside knowledge reality today and in the future when we graduate from school we will encounter Therefore, I really want to apply what I have learned into practice and learn what is lacking Through the help of the subject teacher, I have learned a lot

of things in practice, as well as researched issues and related documents that will help me complete this great exercise Therefore, after considering and

consulting with the teacher, we chose the topic "Audio Amplifier Circuit".

2 Analyze the topic

2.1 System requirements

The circuit has the function of amplifying the input audio

signal 2.2 Function of the circuit

Amplify the audio signal

Minimize the influence of noise and signal interference

Applicable to many sound systems…etc

2.3 Specifications

Use 5V input source

Circuit power 2W

Signal input 50 - 100mV

Load using 8-166Ω speaker

CHAPTER II : BLOCK DIAGRAM

Electricity supply

Input

Loud

CHAPTER III: CHARACTERISTICS AND CALCULATION OF

CIRCUIT SPECIFICATIONS ONLY

1 Principle diagram

Circuit diagram on proteus

2 Circuit parameter calculation

Refer to the datasheet we have:

Q1 has β1=260, Q2 has β2= 200, Q3 has β3= 45, Q4 has β4= 45, Vcc= 5V, Rt=

Rloa= 8Ω

2.1 One-way mode

To bias Q2:

Vb2= Vcc-0,7= 5-0,7= 4,3V

IR4=−2 = 46,7µA

4

Let the amplifier work in the middle of

the static load line:

Vo= 0,5.Vcc= 2,5V

I E1 =I R6 =��2−0,7−��=50µA => Ic1= 50µA

�6

=> Ib1= Ic1/β1 = 0,19µAβ1 = 0,19µA

Ic1=IR4 +Ib2 => Ib2= Ic1- IR4 =3,3µA

=> Ic2= β2.Ib2= 0,66mA =>

Ie2= 0,66mA Mà Ic2= Ib3 =>

Ie3= (β3+1).Ib3=β3+1).Ib3= 30,36mA

Vb4= Vo-0,7= 1,8V

Consider the circuit containing

the Q4 element:

Vo=Ie4.R10+0,7+Ie4.R8

=> Ie4= −0,7= 3,82mA

�10+�

8

Parameter re:

re1=266 = 266 = 520Ω

0,66A 2

=0,86 Ω

266

re3=

266 = 630,36 = 6,8Ω

3

= 26 6

23,82

re4 =626

4

2.2Alternating mode

Floor 1 no-load mode:

+) Take the signal out at terminal C:

Zi= R1/β1 = 0,19µA/β1 = 0,19µAR2/β1 = 0,19µA/β1 = 0,19µAβ1(β3+1).Ib3=re1+ R7)= 21,3k/β1 = 0,19µA/β1 = 0,19µA 395,2k=

20,2 kΩ Zo= R4= 15kΩ

=> Av=−4 = -9,87

+1+

7

+) Take the signal out at E:

Zi= R1/β1 = 0,19µA/β1 = 0,19µAR2/β1 = 0,19µA/β1 = 0,19µAβ1(β3+1).Ib3=re1+ R7)= 21,3k/β1 = 0,19µA/β1 = 0,19µA 395,2k= 20,2 kΩ

Zo= R4= 15kΩ

=> Av= R7/β1 = 0,19µA(β3+1).Ib3=re1+R7)= 0,66

Consider the 2nd floor: Serial push-pull pairing (β3+1).Ib3= Darlington) Consider the Darlington circuit consisting of Q2 and Q3 as a voltage gain transistor:

β=β2.β3+β2+β3= 9254

When there is no load:

When there is a load Rt

Zi2= Zi + β(β3+1).Ib3=Rt+R9)=107,9kΩ

re=2re3=1,72Ω (β3+1).Ib3=Do re= Zi/β1 = 0,19µA(β3+1).Ib3=β2.β3) ;

Zi=2.β2.β3.re3) => Av2= -Rt/β1 = 0,19µA(β3+1).Ib3=re+Rt) = -0,82

* Zi2 of layer 2 also contributes to the load of layer 1:

=> Av1 = -(β3+1).Ib3=R4/β1 = 0,19µA/β1 = 0,19µAZi2)/β1 = 0,19µA(β3+1).Ib3=re1+R7) = -13169/β1 = 0,19µA1520= -8,66 =>

Amplification factor of the whole circuit under load:

Av= Av1.Av2 = 7,1 (β3+1).Ib3=lần)

CHAPTER IV: CIRCUIT SIMULATION AND TESTING

1 Parts list

• R1, R2, R3: Fixed resistor used to reduce the input voltage.

• R4, R6, R11: Resistor used to keep the circuit's ground point at a low level.

• R5, R8: Resistor used to limit the input current.

• R7: Resistor used to balance the output voltage level of the circuit.

• R9, R10: Resistors used to reduce signal distortion in the output.

• C1: Capacitor used to eliminate input signal noise.

• C2, C3, C4, C5, C6: Capacitor used to filter the output signal.

• Q1: Q2: - PNP transistor used to amplify the input signal.

• Q3: NPN transistor used to amplify the output signal.

• Q4: PNP transistor used to amplify the output signal.

• Speaker: 8Ω - 2W - Speaker used to output the amplified audio signal.

• D1/β1 = 0,19µAD2: 1N4148 - Diodes used to protect the transistors from reverse voltage.

Input:

The input audio signal is fed into the circuit through resistors R1, R2 and R3, and then the noise signal is removed through the capacitor C1

After passing through R1, R2 and R3, the audio signal will enter transistors Q1 and Q2 to be amplified

Output:

The amplified audio signal is fed to transistors Q3 and Q4 for further

amplification and output to the speaker

The output of the circuit is an audio signal that has been amplified and passed through the speakers to produce a louder and higher

quality sound than the original input audio signal

2 Simulation circuit

Full circuit diagram simulated on Proteus

Oscilloscope simulation

CHAPTER V: CONCLUDE

- Through working time, with the enthusiastic guidance of Dr.Nguyen Vu Anh Quang, we have achieved the following results:

- Design and manufacture audio amplifier circuit that can be used widely

- Achieve original goals and requirements

- Apply a lot of knowledge about power amplifier in the construction process

- Learn more templates that can be used later

- Refer to many good ideas, have a lot of creativity in design

- The ability to find documents on the network

In the strong development of today's electronic technology and the applications of electronics in life as well as for entertainment are increasingly focused We come to this topic with the desire and also our passion, to create electrical circuit products that are applied in real life