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Technology Park Malaysia

MODULE TITLE

: ANALOGUE ELECTRONICS

(EE001-3-5-2-AE)ASSIGNMENT TITLE : INDIVIDUAL ASSIGNMENT(AUDIO AMPLIFIER)

STUDENT NAME

: GURSHEN SINGH A/LGURUCHARAN SINGH

STUDENT ID

: TP017639

INTAKE

: UC2F1001 EE

SUBMISSION DATE : 17/5/2010

LECTURER S NAME : MR. SARVESWARENKARUNANITHI

ACKNOWLEDGEMENT

First of all, I would like to thank and present my gratitude to the supreme God for giving me the strength to complete this assignment. The assignment includes contribution from numerous people for their kind cooperation in providing the necessary information and support that I need for completing this assignment. I really appreciate their ideas and suggestions and its helped me a lot by physically and mentally in completing this assignment both directly and indirectly. Special thanks to my lecturer, Mr. Sarveswaren Karunanithi for helping me to enhance the contents found for this assignment. He have given me a lot of guidance by reviewing the progress of my assignment from time to time and also motivating and supporting me to ensure that I will be able to come out with quality content in this assignment. Last but not least, I owe a big thanks to the people around me especially my friends, who have been working together with me and supporting me throughout this assignment. Thanks to all of you for your valuable support.

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TABLE OF CONTENTSINTRODUCTION ................................ ................................ ................................ ................ 4 OBJECTIVE ................................ ................................ ................................ ......................... 4 WORK PROGRAM................................ ................................ ................................ .............. 5 ANALYSIS TECHNIQUES ................................ ................................ ................................ . 5 THE DESIGN ................................ ................................ ................................ ....................... 6 -BIPOLAR JUNCTION TRANSISTOR................................ ................................ ............ 6 -TRANSISTOR CONFIGURATIONS ................................ ................................ .............. 9 -STATE OF TRANSISTOR ................................ ................................ ............................ 11 -COMMON BASE CONFIGURATIONS ................................ ................................ ....... 13 - AND RELATIONSHIPS................................ ................................ .......................... 15

OVERALL CIRCUIT DESIGN ................................ ................................ .......................... 16 ANALYSIS OF CIRCUIT ................................ ................................ ................................ .. 16 CALCULATIONS ................................ ................................ ................................ .............. 17 -DC ANALYSIS ................................ ................................ ................................ ............. 17 -AC ANALYSIS ................................ ................................ ................................ ............. 19 MULTISIM STIMULATIONS ................................ ................................ ........................... 25 DISCUSSION AND CONCLUSION................................ ................................ .................. 27 REFERENCES ................................ ................................ ................................ ................... 29

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INTRODUCTIONAn audio amplifier is an electronic amplifier that amplifies low-power audio signals of signals composed primarily of frequencies between 20 hertz to 20,000 hertz, the human range of hearing to a level which suitable for driving loudspeakers and is the final stage in a typical audio playback chain. This audio amplifier amplifies audio signals with the help of many electronics component which are made up to produce such signals such as transistors, capacitors, resistors and many more. The famous and commonly use device is BJTs (bipolar junction transistors). The invention of the bipolar transistor in 1948 ushered in a revolution in electronics. Technical feats previously requiring relatively large, mechanically fragile, powerhungry vacuum tubes were suddenly achievable with tiny, mechanically rugged, powerthrifty specks of crystalline silicon. This revolution made possible the design and manufacture of lightweight, inexpensive electronic devices that we now take for granted. Understanding how transistors function is of paramount importance to anyone interested in understanding modern electronics. In this assignment, we are required to design a low cost audio amplification circuit using a bipolar junction transistor with the specification of output and input voltage for the used in the budget segment of high fidelity (hifi) sets. Herein, I have included my complete research as well as the requirements which are needed for this assignment. I have also simulated the circuit using multisim software..Finally,I construct the circuit and test it in the lab.

OBJECTIVEThe objective of this assignment is to design and construct a low cost audio amplification circuit for use in the budget segment of high fidelity (hifi) sets.

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WORK PROGRAMDevelop a low cost audio amplification circuit using only bipolar junction transistor (BJT). The audio amplification specifications are input voltage, Vi = 200 mVp-p and output voltage, Vo = 20 Vp-p with 0 phase offset (noninverting).

ANALYSIS TECHNIQUESThe audio amplifier specifications are as follows: i) ii) iii) Input: Output: 200 mVp-p 20 Vp-p

Phase offset: 0r (non-inverting)

In order to solve this problem, it is advisable to use the appropriate hybrid pi model and refer to the BJT data sheet to find out the early voltage of the transistor. Perform simulations using Multisim to assess how the circuit would perform under nominal conditions. Methodology: a. Voltage gain, Av calculation based on the given specification. b. Draw the hybrid pi model. c. Design the circuit using both DC and AC analysis. d. Ensure that the resistance values used is nominal standard resistance values. e. Verify the design circuit by using Multisim. f. Construct the circuit in the lab to calculate the voltage gain and to display both input and output waveforms.

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T EBI The i L

E ITI T I T t nsistor in 1948 ushered in a revolution in electronics. large, mechanicall fragile, powerhungry -

enti n of the bi ol

Technical feats previousl

requiring relativel

vacuum tubes were suddenly achievable with tiny, mechanically rugged, powerthrifty specks of crystalline silicon. This revolution made possible the design and manufacture of lightweight, inexpensive electronic devices that we now take for granted. Understanding how transistors function is of paramount importance to anyone interested in understanding modern electronics. A bipolar transistor consists of a three-layer sandwich of doped (extrinsic) semiconductor materials, either P-N-P or N-P-N. Each layer forming the transistor has a specific name, and each layer is provided with a wire contact for connection to a circui . t

Figure 1: PNP & NPN transistor

The functional difference between a PNP transistor and an NPN transistor is the proper biasing (polarity) of the junctions when operating. For any given state of operation, the current directions and voltage polarities for each kind of transistor are exactly opposite each other.

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Bipolar transistors work as current-controlled current regulators. In other words, transistors restrict the amount of current passed according to a smaller, controlling current. The main current that is controlled goes from collector to emitter, or from emitter to collector, depending on the type of transistor it is (PNP or NPN, respectively). The small current that controls the main current goes from base to emitter, or from emitter to base, once again depending on the kind of transistor it is (PNP or NPN, respectively). According to the standards of semiconductor symbo logy, the arrow always points against the direction of electron flow as shown in the figure below;

Figure 2: PNP and NPN transistors and their p-n junctions Small electron base current controls large collector electron current flowing against emitter arrow. Bipolar transistors are called bipolar because the main flow of electrons through them takes place in two types of semiconductor material: P and N, as the main current go from emitter to collector (or vice versa). In other words, there are two types of charge carriers, electrons and holes which comprise this main current through the transistor. Thus, the controlling current and the controlled current always mesh together through the emitter wire, and their electrons always flow against the direction of the transistor's arrow. This is the first and foremost rule in the use of transistors: all currents must go in the proper directions for the device to work as a current regulator. The small, controlling current is usually referred to simply as the base current because it is the only current that goes through the base wire of the transistor. Conversely, the large, controlled current is referred to as the collector current because it is the only current that goes through the collector wire. The 7

emitter current is the sum of the base and collector currents, in compliance with Kirchhoff's Current Law. No current through the base of the transistor, shuts it off like an open switch and prevents current through the collector. A base current, turns the transistor on like a closed switch and allows a pr