DESIGN & CONSTRUCTION OF 3-INPUT PUBLIC ADDRESSING SYSTEM
INTRODUCTION
A public address system is an electronics sound amplification and distribution system with a microphone, amplifier and loud speaker used to allow a person to address a large public.
The public address system consists of three main parts namely, the microphone (input transducer), amplifier and the loudspeaker (output transducer).
The microphone picks up the sound and convert it to
electronic signal in milivolts and this is fed to the amplifier for amplification. In this project, a dual operational amplifier (OP-Amp) 1458 IC is used for the amplifications. The amplifier has two sections; the Pre-Amp and the power –AM. The pre-amp does the first boosting of the input audio signal to a level handleable by the last stage of the amplifier called power amp. This early stage (pre-amp) is designed to give good voltage gain. Hence the pre-amp is referred to as the voltage amplifier. The last amplifier stage is the power amp and is the stage that typically requires most attention; the power efficiency.
After the amplifier stage, the very small input signal is then magnified to a larger version and is fed to the speaker for conversion to sound. The speaker is an electromagnetic device that operates on the principle of electromagnetic
induction and with the help of its component converts electrical signal to sound.
Title Page———i
Certification——–ii
Dedication———iii
Acknowledgement——-iv
Abstract ———vi
Table of Content——–vii
Chapter One
1.0 Introduction ——-1
1.1 Statement of Problem——4
1.2 Purpose of the Study——5
1.3 Significance of Study——8
1.4 Limitation——–9
1.5 Scope of Study——-11
Chapter Two
2.0 Review of Related Literature —-12
2.6 Summary of Literature Review—- 19
Chapter Three
3.0 Research Methodology and Procedure—22
3.1 Population ——–22
3.2 Sample and Sampling Technique—-22
3.3 Validation of the Instrument —-23
3.4 Reliability of the Instrument —–23
3.5 Data Analysis——-23
Chapter Four
4.0 Presentation and Discussion of Result—24
4.1 Analysis and interpretaion of Data—25
4.2 Discussion of Results——38
Chapter Five
5.0. Summary, Conclusion, and Recommendation –40
5.1 Summary——–40
5.2 Conclusion——–41
5.3 Recommendation——42
References ———45
Appendix 1——–47
Appendix ———50
DESIGN & CONSTRUCTION OF 3-INPUT PUBLIC ADDRESSING SYSTEM
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