Description
ABSTRACT
This work is on design of a digital voltmeter for AC/DC voltage measurement using PIC microcontroller. This design uses the PIC microcontroller, rectifier, voltage divider and seven segment displays to complete the desired measurement. This meter is calibrated for the measurement of upto 500 volts. Here we are using PIC microcontroller because this is having an internal ADC, however any other microcontroller can be used with or without internal ADC. But separate ADC is required if microcontroller used is without internal ADC.
Digital voltmeters can measure a range of alternating current (AC) voltages, direct current (DC) voltages, or both AC and DC voltages. Devices typically display between three and seven digits.
TABLE OF CONTENTS
COVER PAGE
TITLE PAGE
APPROVAL PAGE
DEDICATION
ACKNOWLEDGEMENT
ABSTRACT
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF THE PROJECT
- PROBLEM STATEMENT
- AIM AND OBJECTIVE OF THE PROJECT
- SIGNIFICANCE OF THE PROJECT
- SCOPE OF THE PROJECT
- LIMITATION OF THE PROJECT
- PROJECT ORGANIZATION
CHAPTER TWO
LITERATURE REVIEW
- OVERVIEW OF A VOLTMETER
- TYPES OF VOLTMETER
- HISTORICAL BACKGROUND OF DIGITAL VOLTMETER
CHAPTER THREE
DESIGN METHODOLOGY
- SYSTEM ARCHITECTURE
- SYSTEM BLOCK DIAGRAM
- CIRCUIT DIAGRAM
- OPERATION OF THE PROPOSED SYSTEM
- SYSTEM FLOWCHART
- SOFTWARE IMPLEMENTATION
- SYSTEM CODE
- DESCRIPTION OF MAJOR COMPONENTS USED
CHAPTER FOUR
TESTING AND RESULTS
- CONSTRUCTION PROCEDURE AND TESTING
- INSTALLATION OF THE COMPLETE DESIGN
- ASSEMBLING OF SECTIONS
- TESTING OF SYSTEM OPERATION
- SYSTEM SAFETY
CHAPTER FIVE
- CONCLUSION
- RECOMMENDATION
CHAPTER ONE
- INTRODUCTION
1.2 BACKGROUND OF THE STUDY
Digital voltmeter is an instrument that measure voltage or voltage drop in a circuit. Digital voltmeter uses solid-state components and display values digitally. Typically, Digital voltmeters (digital volt meters) can be used to locate excessive resistance that may indicate an open circuit or ground. They are also used to identify low voltage or voltage drops that may indicate a poor connection. The positive lead is connected to the circuits positive side and the negative lead is connected to the circuits ground. The digital voltmeters internal resistance is the impedance, which is usually expressed in ohms per volt. This amount is relatively high in order to prevent the device from drawing significant current and disturbing the operation of the circuit being tested. The sensitivity of the Volt meter determines the range of voltages that digital voltmeters can measure.
Digital voltmeters can measure a range of alternating current (AC) voltages, direct current (DC) voltages, or both AC and DC voltages. Some digital voltmeters can capture minimum and maximum voltages called spike readings. Others measure the root mean square (RMS), a range of frequencies, or the signal power in decibels.
This work is aimed at building a digital AC/DC voltmeter (DVM) which measures an unknown input voltage by converting the voltage to a digital value and then displays the voltage in numeric form through an LCD.
1.2 PROBLEM STATEMENT
Digital voltmeter was built to overcome challenges seen in analogue meter. Analog voltmeters have pointer across a scale in proportion to the voltage of the circuit. Analogue voltmeter have interpolation errors and have moving parts. Whilst digital meters are more accurate than analog multimeters. They reduce reading and interpolation errors. In digital meters, parallax errors are eliminated. Digital multimeter displays have no moving parts. This makes them free from wear and shock failures.
1.3 OBJECTIVE OF THE PROJECT
The main aim of this work is to construct digital voltmeter for AC/DC measurement, which is one of the general requirements for any electrical circuit. The objectives are:
- To determine the value of an AC or DC voltage in a digital form.
- To increase accuracy and repeatability this circuit is designed using a microcontroller which also minimize the other electronic circuitry.
- To improve the overall performance of the voltmeter
1.4 SIGNIFICANCE OF THE PROJECT
Carrying out this work is a way of making student involved conversant with the programming of PIC microcontroller controller.
This study will help readers of the work to understand the advantages of digital voltmeter over analogue. This implementation is work will help the student to know how to build a
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rugged and very much reliable voltmeter.
1.5 SCOPE OF THE PROJECT
The scope of this work covers building digital voltmeters give a numerical display of voltage by use of an analog to digital converter. A digital voltmeter (DVM) measures an unknown input voltage by converting the voltage to a digital value and then displays the voltage in numeric form. DVMs are usually designed around a special type of analog-to-digital converter called an integrating converter.
1.6 LIMITATION OF THE PROJECT
- The LCD display depends on a battery or external power source. When the battery is low, the display will be dim, making it difficult to read.
- There is a voltage limitation. If it is increased beyond the limit, the meter will be damaged.
- They are expensive due to high manufacturing cost.
1.7 PROJECT WORK ORGANIZATION
The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:
Chapter one of this work is on the introduction to a digital voltmeter. In this chapter, the background, significance, objective limitation and problem of a digital voltmeter were discussed.
Chapter two is on literature review of a digital voltmeter. In this chapter, all the literature pertaining to this work was reviewed.
Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.
Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.
Chapter five is on conclusion, recommendation and references.
CHAPTER FIVE
5.1 CONCLUSION
This project has been successfully designed, constructed and also tested for the specified range. This voltmeter is calibrated with 0.1volt of resolution upto 99.9 volts and of 1volt of resolution from 100 volts onwards. It is relatively cheaper voltmeter, comparing to those present in the market. This research will enhance the possibility of using digital voltmeters to improve micro, small and medium scale industries in the country.
The voltmeter can utilize a variety of test probes to connect to the circuit or device under test. Crocodile clips, retractable hook clips, and pointed probes are the three most common attachments. Tweezer probes are used for closely spaced test points, as in surface-mount devices. The connectors are attached to flexible, thickly insulated leads that are terminated with connectors appropriate for the meter.
The banana jacks are typically placed with a standardized center-to-center distance of 0.75″ (19.05mm), to allow standard adapters or devices such as voltage multiplier or thermocouple probes to be plugged in.
Clamp meters clamp around a conductor carrying a current to measure without the need to connect the meter in series with the circuit, or make metallic contact at all.
5.3 RECOMMENDATION
The device (digital ac/dc voltmeter) has been designed, tested and system was able to respond to its operation. This work was built with quality wiring and contains many connections, I recommend that if failure occur, it should be troubleshoot by a qualify personnel along with the circuits diagram.
Working on this topic (digital ac/dc voltmeter) as my project is a good idea and it comes at the right time. I am suggesting that this particular topic should also be given to other students both in higher and lower class.
