This project work “design and construction of digital trainers for electrical/electronics and computer engineering laboratory and workshop” analyzes the roles played by training kits in electrical/electronic and computer engineering laboratories as well as the role of laboratory and field-based research as it affects Engineering as profession, basic approaches towards how trainers are built are analyzed. In all, about ten different were designed and constructed. Processes involved in electrifying a building by taking into account a step by step calculations required in order to have a suitable output which will be professionally acceptable was also critically looked into. Classroom and field-based “lab work” is conceptualized as central components of broader scientific investigations of the natural world conducted by students. Considerations are given to nature of professional scientific practice, the personal relevance of student’s understanding of the nature of empirical scientific research, and the role of technology to support learning. In summary at the end of the whole design, it could be clearly seen that; laboratory investigation holds significant promise for being able to support conceptual and epistemological learning when facilitating conditions are put in place for students especially when approached from the perspective of designing and constructing the kits needed to carry out this research as employed in this my project work that dealt with the construction the local design and construction of the training kits.


Title Page




Table of Content

List of Figures

List of Tables



  • Introduction                                                                                                                1

1.1       Background of the Project                                                                                          3

1.2       Aims                                                                                                                            3

1.3       Objectives                                                                                                                   4

1.4       Problem statement                                                                                                      4

1.5       Scope of the Project                                                                                                    4



2.1       Literature Review                                                                                                       6

2.1.1    Seven segment                                                                                                            6

2.1.1    NE 555 timer                                                                                                              7

2.2       Concept and Visual Structure                                                                                     8

2.2.1    Seven segment visual structure                                                                                   8

2.2.2    NE 555 timer                                                                                                              10

2.3       Application                                                                                                                 11

2.3.1    Seven segments                                                                                                           11

2.3.2    NE 555 timer                                                                                                              13

2.4       BCD to Seven Segment Demonstration Board /Trainer                                             13

2.5       Power Supply Unit                                                                                                     15

2.6       NE 555 Timer Trainer                                                                                                 17



  • Design Methodology                                                                                                  19

3.1.1    Binary Coded Decimal                                                                                               19

3.1.2    NE555 Timer Trainers                                                                                     21

3.2       Description                                                                                                                  23

3.2.1    BCD to 7 Segment Decoder                                                                                       23

3.2.2    NE 555 timer                                                                                                              25 NE 555 Timer as Monostable Multivibrators                                                              27 NE 555 timer as Astable Multivibrators                                                                     30

3.3       Hardware Design and Analysis                                                                                  36

3.3.1    Power Supply Unit                                                                                                     36

3.3.2    Power Indicator Circuit                                                                                              39

3.4       Construction                                                                                                               41

3.5       Hardware tools                                                                                                           43



4.0       Results and Discussion                                                                                               44

4.1       Introduction                                                                                                                44

4.2       System Operation                                                                                                       44

4.3       Device Testing                                                                                                            45

4.4       Components testing                                                                                                    45

4.5       Wiring testing                                                                                                             45

4.6       System testing                                                                                                             45

4.7       Discussion of result                                                                                                     45



5.1       Introduction                                                                                                                54

5.2       Cost analysis                                                                                                               54

5.3       Conclusions                                                                                                                 54

5.4       Problems Encountered                                                                                                54

5.5       Recommendation and Future works                                                                           54

References                                                                                                                  55



2.1       Seven segments                                                                                                           8

2.2       NE 555 timer structure                                                                                               10

2.3       BCD to seven segment trainers                                                                                  14

2.4       DC power supply unit                                                                                                 16

2.5       NE 555 timer                                                                                                              18

2.6       Pin description                                                                                                            18

3.0       BCD to 7 Segment Decoder                                                                                       24

3.1       BCD to 7 Segment Decoder Description                                                                   24

3.2A    IC 555 in 8 pin dip package                                                                                        26

3.2B    Functional block diagram of IC 555                                                                           26

3.3       Monostable Multivibrators trainers                                                                             29

3.4       Rectangular Waveform                                                                                               31

3.5       Astable Multivibrators circuit diagram                                                                       31

3.6       Astable Multivibrators circuit diagram with less than 50% duty cycle                      34

3.7       Astable Multivibrators trainers circuit diagram                                                          35

3.9       Block diagram showing rectification process                                                             37

3.9.1    D.C Power supply circuit                                                                                            37

3.9.2    Power Indicator Circuit                                                                                              39



3.0       Binary pattern                                                                                                             20

Devices Plate

3.0       Complete BCD to 7 Segment demonstration trainers with Power Supply                41

3.1       Soldered P.C.B                                                                                                           42

3.2       Seven Segment Trainers                                                                                              42




Engineering as a profession is such; that revolves round the concept of implementing what is theoretically taught in the class; practically in the laboratory. This is why laboratories are made compulsory to be part of what is needed in any institution of learning where science and engineering related courses are taught.

It is a well-known fact that science students are groomed right from secondary school; to have this practical based mindset. For example, under chemistry, they were taught acid/base titration etc. to confirm the truth about the behavior of the relationship between base and acid. This greatly helps student in understanding the concept of this relationship when they are taught theoretically.

This concept now extends to higher institutions for student who have science background, one of which is engineering as a whole. But, it is rather unfortunate that most of the apparatus and equipment used in the laboratories are imported.

The Bells university of technology; being a school of technology now deems fit for this problem to be given a positive approach and this has been, the main reason why student are encourage to develop and design trainers as their final year project.

Apart from trainers being built, a chance of showcasing another technical knowledge was also given to them. This has to do with electrical wiring done in some of our laboratories in the course of setting them up. In all, four laboratories and one workshop were worked on. Wiring was done in all these places; this gave me a practical exposure towards putting my professional ability in use. I did load calculations for each of the laboratories in order to make an adequate selection of cables with proper consideration given to the current carrying capacity for each of the selected cable.

Apart from these, technology has been said to be the bedrock of development globally, no one can talk about development as far as technology is concerned without making reference to engineering as a profession. Therefore, it won’t be wrong to say that engineering is the bedrock of development.

The reason behind this statement is not farfetched; it is because engineers are trained to demonstrate what they are taught practically. This is not possible without going through different experimental processes in the laboratory in order to establish the fact that all the principles taught theoretically in the classroom is true. Different concepts are demonstrated in the laboratory, as pleasant as this sounds, it is rather unfortunate that most of the equipment used in the laboratories are imported.

That was why the department of electrical and electronics of Bells university feels that it is very important to work towards developing some of this trainers, as well as setting up the laboratories, in the course of setting up the laboratories, different calculations were carried out, some of these include load calculation in order to determine the appropriate cable sizes for each section of the laboratories.

It is worth mentioning here that some ready-made trainers were selected for construction with the mindset of improving on their performances. Appropriate designs were done for each of the trainers as will.

1.1       Justification

Justification of the project can be established if consideration is given to amount of money spent on importing these project as well as the time duration to bring them in. also It is well justified that; if the unit is built locally, that would have spelt a land mark achievement for the school as entity.

1.2       Background of the Project

The trainers designed are built around basic common components that are available for use under electrical/electronic as a profession, proper designs were done for each of the trainers. On the aspect of setting up the laboratories, proper considerations were given to the size of each laboratory; which served as one of the determining factors in taking decisions on many things that were put in place in the laboratories.

1.3       Problem Statement

The main aim behind this project “design and construction of digital trainers for electrical/electronics and computer engineering laboratory and workshop” is to set up different laboratories and to construct laboratory trainers locally for these laboratories.

1.3       Objectives

The objectives behind this project work are:

  • To wire up 4 laboratories and 1 workshop in the department of Electrical/electronic and Computer of the Bells university of technology.
  • To design and construct; some trainers for use in these laboratories.
  • To verify the way some the components we have leant about theoretically actually behave in a real practical situation.
  • To develop manuals; for the conduct of practical in these laboratories.
  • To design and construction of digital trainers for electrical/electronics and computer engineering laboratory and workshop

1.4       Scope of the Project

The scope of the project is to utilize basic electrical/electronic components to design these under listed laboratory trainers:

BCD to seven segment decoder/project board.

Alternative power supply trainer.

Project board.

Contactor trainer.

Microcontroller/LCD trainer.

OP-AMP trainer.

Seven segment demonstration board.

NE555 timer/ decade counter trainer.

Power transmission demonstration board.

And also, the electrification of 4 laboratories and 1 workshop.

1.5       Significance of the Project

The relevance of this project work cannot be over emphasized if the following arguments are given proper considerations.

First and foremost, the cost of procuring laboratory trainers is on the high side when compared to the ones being constructed locally by me and some of my other colleagues. Apart from this, building these gadgets as exposed many of us who worked on them; the mindset of how experiments are extracted from trainers.

Finally, Bells University of technology being a university of technology can actually prove her worth among universities of Technology globally: if these things we are building is brought into global limelight.

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