ABSTRACT
This work is a power supply monitoring device that triggers a buzzer when the mains supply cuts off. Thus a diode (bridge rectifier diode) was used to convert the AC voltage to DC voltage and the 240v/12v AC mains power transfer was used with a bridge rectifier for rectification and a 470Nf filter capacitor C1 for the smoothing of the voltage. A transformer for stepping down the 240volts was also used before it was rectified. Resistor R1 for reduction of the voltage to power the LED (light emitting diode) was connected between C1 and the ground to indicate when power was off together with the buzzer. This operates in such a way that when there was no mains power available the relay was switched unto its normally closed terminals. At this instance the um66 musical melody IC was energized to produce a continuous stream of tones and this available low audio musical tone was amplified using the 2N3904 transistor such that a much louder audio sound was available at the collector output of the 2N3904 with the aid of the loudspeaker thereby producing a power outage.
Table of contents
Title page i
Certification ii
Dedication iii
Acknowledgement iv
Table of contents v
Abstract viii
CHAPTER ONE
1.0 Introduction 1
1.1 Background of the study 1
1.2 Statement of the problem 2
1.3 Objective of the study 3
1.4 Significance of the study 3
1.5 Scope f the study 3
CHAPTER TWO
2.0 LITERATURE REVIEW 4
2.1 Description 7
2.2 Transformer 7
2.3 Capacitor 9
2.4 Transistor 10
2.5 Diodes 12
2.6 Electromagnet relay (LED) 13
2.7 Contact 14
2.8 Resistor 15
2.9 Battery 16
2.10 Loud speaker 17
2.11 Bridge rectifier 18
2.12 Integrated circuit um66 18
CHAPTER THREE
3.0 Material and method 20
3.1 AC Input 20
3.2 Power supply circuit 20
3.3 The switch circuit 22
3.4 Back of battery circuit 22
3.5 Alarm circuit 23
3.6 Loud speaker 23
3.7 The circuit diagram 24
3.8 Construction 24
3.9 The casing construction 25
3.10 Tools used for the construction 26
CHAPTER FOUR
4.0 Test and result 27
4.1 Result 28
CHAPTER FIVE
5.0 discussion 29
5.1 Problem encountered 29
5.2 Solution 29
5.3 Recommendation 30
5.4 Conclusion 31
References 32
