1.1 Introduction
Digital Trainer is a self contained set of electronic circuits that can be interlinked by students to create working circuits. Component parts cannot be removed or lost in the classroom and interlinking is performed by short coloured cables fitted with small insulated alligator clips. The Digital Trainer is a general-purpose digital experiment board equipped with different built-in circuits as well as a standard PB-501 breadboard. There are: 8 Data Switches - The data switch circuits provides eight DATA OUTPUT pins D1 to D8 whose output level is adjusted using slide switches. As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
In World War II, mechanical analog computers were used for specialized military applications such as calculating torpedo aiming. During this time the first electronic digital computers were developed, with the term digital being proposed by George Stibitz in 1942. Originally they were the size of a large room, consuming as much power as several hundred modern PCs (ENIAC, 2009).
Digital logic is the processing of only two states or conditions of ON and OFF. There are certain electronic chips (called gates) that convert simple on and off conditions to create a third on or off condition. The basic gates are AND, OR, NAND, NOR and NOT. These digital gates are explained and a combination of these simple gates in various configurations permits more complex logic or counting and maths to be computed. When prototyping digital electronic circuits, the digital circuits require specific digital (0-5V) input signals, which then generate digital (0-5V) output signals for monitoring. To accomplish this task a teaching device known as a ‘Digital Trainer’ is utilised. The trainer includes (among other functions) switches for providing digital logic inputs and LED indicators to specify digital logic outputs.
Unfortunately it is impractical to loan out these digital trainers to students, for reason such as: the limited number of digital trainers (compared to the student numbers); the need to use the trainers in multiple repeat laboratories; and the effort required to replace any lost boards. Additionally, the cost of the digital trainer boards makes it unfeasible for students to purchase their own board. Hence students are limited to using the digital trainers within their scheduled laboratory sessions, which inhibits the students gaining extended practice in order to improve their skills.
To provide a method for students to test digital circuits outside the scheduled laboratory times, this device was introduced. The work is a simple and inexpensive limited version of a digital trainer. The device needed be simple enough for the students to construct themselves, and to be affordable enough so that the students could permanently retain the device. The result was the ‘PortBuffer’ system; its development and implementation is described in the following sections.
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to design and construct a digital trainer board.
1.3 Statement of Problems
Investigation revealed that digital circuits are made from analog components. The design must assure that the analog nature of the components doesn't dominate the desired digital behavior. Digital systems must manage noise and timing margins, parasitic inductances and capacitances. Bad designs have intermittent problems such as glitches, vanishingly fast pulses that may trigger some logic but not others, runt pulses that do not reach valid threshold voltages (Wikipedia, 2021).
Additionally, where clocked digital systems interface to analog systems or systems that are driven from a different clock, the digital system can be subject to metastability where a change to the input violates the setup time for a digital input latch. Since digital circuits are made from analog components, digital circuits calculate more slowly than low-precision analog circuits that use a similar amount of space and power. However, the digital circuit will calculate more repeatably, because of its high noise immunity (Wikipedia, 2021).
1.4 Aim and Objectives of Study
The aim of the study is to design and construct a digital trainer board. In achieving this aim, the following specific objectives were laid out as follows:
- To construct a training modules which display its output via seven segment display
- To design and construct a cost effective and reliable digital trainer board
- To design an inexpensive, simple to use device that could be retained by students, so that they could undertake digital experimentation in school or at home.
- To provide further and more extensive studies about some important digital circuits.
1.5 Significance of Study
The Digital Trainer is a general-purpose digital experiment board equipped with different built-in circuits as well as a standard breadboard. It is as a flexible instructional aid for academic institutions and a powerful development kit in Labs. This study will be of immense benefit to other researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.
1.6 Scope of Study
The scope of the research is focused on the design and construction of a digital trainer board. Digital training module to do more work per unit time is to accept that they generate more heat, and somehow this power needs to be got in (as electricity), and then got out again (as waste heat). It is the latter which is causing the greater problems (and has done for most of the time since the invention of the integrated circuit).
1.7 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- 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).
1.8 Organization of Research Work
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 research work is on the introduction to the study. In this chapter, the background, significance, objective limitation and problem of the study were discussed.
