Design And Construction Of A Variable Dual Supply

ABSTRACT

This project work is on design of a variable dual power supply. This work describes how to design a variable dual power supply circuit. The main advantage of this power supply circuit is that it can vary the negative and positive output voltage and current.

A variable dual power supply supplies adjustable level of electric energy to an electrical load. The primary function of a variable dual power supply is to supply variable positive and negative output voltage which can be used to power devices.

TABLE OF CONTENTS

 TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

• INTRODUCTION
• BACKGROUND OF THE PROJECT
• PROBLEM STATEMENT
• AIM/OBJECTIVE OF THE PROJECT
• PURPOSE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• SCOPE OF THE STUDY
• LIMITATION OF THE PROJECT
• APPLICATION OF THE PROJECT
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

2.0      LITERATURE REVIEW

2.1      REVIEW OF POWER SUPPLY

2.2     REVIEW OF POWER SUPPLY CHARACTERISTICS

2.3      REVIEW OF GENERAL APPLICATION OF POWER SUPPLY APPLICATIONS

2.4       REVIEW OF TYPES OF POWER SUPPLY

CHAPTER THREE

3.0      CONSTRUCTION METHODOLOGY

3.1      BLOCK DIAGRAM OF THE SYSTEM

3.2      BLOCK DIAGRAM DESCRIPTION

3.3      CIRCUIT DIAGRAM

3.4      CIRCUIT DESCRIPTION

3.7      SYSTEM OPERATION

3.8     CIRCUIT DESCRIPTION

3.9     DESCRIPTION OF MAJOR COMPONENTS USED

CHAPTER FOUR

4.0       RESULT ANALYSIS

4.1      CONSTRUCTION PROCEDURE AND TESTING

4.2      ASSEMBLING OF SECTIONS

4.3      CONSRUCTION OF THE CASING

4.4     TESTING

4.5     INSTALLATION OF THE COMPLETED DESIGN

CHAPTER FIVE

• CONCLUSIONS
• RECOMMENDATION
• REFERENCES

CHAPTER ONE

• INTRODUCTION

1.1                                            BACKGROUND O THE STUDY

A power supply is an electronic device that supplies electric energy to an electrical load. The primary function of a power supply is to convert one form of electrical energy to another and, as a result, power supplies are sometimes referred to as electric power converters. Some power supplies are discrete, stand-alone devices, whereas others are built into larger devices along with their loads according to US patent #4937722.

Every power supply must obtain the energy it supplies to its load, as well as any energy it consumes while performing that task, from an energy source. Depending on its design, a power supply may obtain energy from various types of energy sources, including electrical energy transmission systems, energy storage devices such as a batteries and fuel cells, electromechanical systems such as generators and alternators, solar power converters, or another power supply (Torres, 2008).

All power supplies have a power input, which receives energy from the energy source, and a power output that delivers energy to the load. In most power supplies the power input and output consist of electrical connectors or hardwired circuit connections, though some power supplies employ wireless energy transfer in lieu of galvanic connections for the power input or output. Some power supplies have other types of inputs and outputs as well, for functions such as external monitoring and control (Torres, 2008).

To obtain a complete circuit for this work, the circuit is mainly composed of the:

• Input transformer:   The input transformer is used to transform the incoming line voltage down to the required level for the power supply. Typically the input transformer provides a step down function. It also isolates the output circuit from the line supply.
• Rectifier:   The power supply rectifier converts the incoming signal from an AC format into raw DC. Either half wave or more commonly full wave rectifiers may be used as they make use of both halves of the incoming AC signal.
• Smoothing:   The raw DC from the rectifier is far from constant falling to zero when the AC waveform crossed the zero axis, and then rising to its peak. The addition of a reservoir capacitor here fills in the troughs in the waveform, enabling the next stage of the power supply to operate. Large value capacitors are normally used within this stage.
• Positive and negative Voltage adjuster:   This stage of the power supply takes the smoothed voltage and uses a variable ic and potentiometer to provide a variable regulated output virtually regardless of the output current and any minor fluctuations in the input level.

The aim of the dual adjustable power supply circuit is to provide power for other projects that require a dual (+/-) adjustable power supply.

1.2                                                  PROBLEM STATEMENT

For prototyping and hobbyists, appliances or gadget with smaller voltages and dual input voltages, in this case, battery cannot be use because batteries have only positive and ground. To solve this problem a variable dual DC power supply can be used which is implemented in this project.

1.3                                                   AIM OF THE PROJECT

The main aim of this work is to build a dual adjustable power supply circuit which provides power for other projects that require a dual (+/-) adjustable power supply.

1.4                                                 SCOPE OF THE PROJECT

1. This device was built to supply DC voltage of 0V to 30V.
2. it Can provide DC dual variable on positive, negative and ground, are +/- 0-30 volts.

iii. It Can supply current out the maximum of about 1.5 A.

337. it used the most popular IC are LM317T and LM337.

1.5                                         SIGNIFICANCE OF THE PROJECT

This work makes it possible for someone to use one power supply to run different devices of higher or lower voltage rating without considering buying a new or different power supply.

LIMITATION OF STUDY

As we all know that no human effort to achieve a set of goals goes without difficulties, certain constraints were encountered in the course of carrying out this project and they are as follows:-

1. Difficulty in information collection: I found it too difficult in laying hands of useful information regarding this work and this course me to visit different libraries and internet for solution.
2. Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet)

• Time Constraint: The researcher will simultaneously engage in this study with other academic work. This consequently will cut down on the time devoted for the research work.

1.6                                          APPLICATION OF THE PROJECT

A variable dual power supply is a regulator that electricians and electrical project hobbyists use to test the capacity of voltage for any project they may have completed. The power supply is used as a gauge to make sure the piece of work the person has completed is able to withstand certain amounts of voltage and current load. Tests are generally conducted by applying different amounts of voltage to the piece of completed work a little at a time to ensure the stability of the circuit the individual has created. These types of power supplies also are used by hobbyists to power small electronics requiring variable voltage and by tattoo artists to power tattooing guns (Torres, 2008).

1.7                                                         PROJECT ORGANISATION

The work is organized as follows: chapter one discuses the introductory part of the work,   chapter two presents the literature review of the study,  chapter three describes the methods applied,  chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.