Combinational Logic Circuit:

Truth Table, POS and Boolean Expression, and Boolean Algebra Simplifications

Objectives

The experiment aims to help students to gain hands-on experience on designing and implementing a Digital Logic circuit that solve a real-life problem. Furthermore, students will learn experimentally how simplify the logic function using Boolean algebra rules can improve the overall efficiency and reduce the cost of the digital logic circuits. During this experiment, students will apply the following aspects of logic design:

Building a logic circuit based on its logic equation in SOP or POS forms
Derivation of a truth table based on problem description
Logical expressions minimization
Writing up a simple combinational logic circuit from a logic diagram
Verifying the operation of a simple logic circuit by comparing performance with a given specification
Further use of TTL data sheets

Preparation before the lab

Design a logical circuit to be part of a 3-person voting system. The "Yes" light turns ON onlyif the majority has pressed on the "Vote" button.

Generate its Truth table.
Drive its POS & SOP expressions.

Simplify the SOP using Boolean algebra to obtain the following expression.

f(A,B,C)=A.B+A.C+B.C

Simplify the POS using Boolean algebra to obtain the same expression in (3).

Draw the corresponding logic diagram.

Equipment and Components

74LS04 IC - Hex Inverters
74LS32 IC - 2-Input OR Gates
74LS08 IC - 2-Input AND Gates
THE ETS-81001 Digital Trainer board

Experiment Task and Procedure

1) Wire up the logic system based on the minimized SOP expression you drawn in the preparation part. You are advised to start by thinking about where best to physically place all components on the breadboard and then make all the Vcc (5Volts) and GND connections. Only then should you start wiring the actual logic signal interconnections. You must also carefully and methodically tick off each signal connection one-by-one on your schematic as you go along and make a note on your diagram of the actual colours you choose.

2) Apply all possible combinations of logic levels to the inputs and verify that the system performs as specified.

3) Repeat (1) and (2) for the logic system based on the POS expression.

Instructions for Report

Students should include a cover page mentioning lab number, title, course, instructor, GTA and students information. Then the report should include following sub-sections:

1. Objectives
This should describe the aim of this particular lab you have carried out.

2. Introduction and Experiment description
This should include introduction to the experiment topic and problem statement of the experiment (description of the problem to be solved or implemented)

3. Pre-lab work
Here you should show your work for the preparation part(s) (you should do it before conduct your experiment).

4. Experiment procedure and steps
Describe the steps that you perform to conduct the experiment

5. Result & Discussion

In this section, you should discuss your results and summarize the learning outcomes that you have achieved after conducting the experiment.

Attachment:- Appendix.rar