Digital Electronics and Logic Circuits (CSCT2202)
Computer Science - COS
Semester: Second Semester
Level: 200
Year: 2016
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SCHOOL: H.T.T.T.C DEPARTEMENT: CS LECTURER(S): Dr. DADA Jean-Pierre
COURSE CODE: CSC122 COURSE TITLE: Digital electronics and logic circuits OPTION: FCS100
DATE: July ….. 2016 HALL: ………… TIME: 2:00 NATURE: Exam
Instructions:…… Answer all questions…………..
Exercise 1: Give the logic functions performed by the following schematics (8 marks):
1.1) 1.2)
Exercise 2: A logic function is defined as: 𝑆 = 𝐴
𝐵
𝐶
+ 𝐴
𝐵
𝐶 + 𝐴𝐵
𝐶
+ 𝐴𝐵
𝐶. Simplify this function
using the following methods:
1) Algebraic method (5 marks)
2) Karnaugh map (5 marks)
3) Quine Mc Cluskey method (5 marks)
4) Conclude by comparing the results obtained (4 marks)
Exercise 3: The following schemes are Karnaugh tables, simplify the logic functions (12 marks):
3.1) 3.2) 3.3)
Exercise 4 (16 marks): En enterprise wants to recruit engineers for immigration in an American continent.
The Boolean variables chosen are the following:
REPUBLIC OF CAMEROON
Peace – Work – Fatherland
***********
THE UNIVERSITY OF BAMENDA
***********
HIGHER TECHNICAL TEACHER TRAINING
COLLEGE (H.T.T.T.C.) BAMBILI
***********
DIRECTORATE OF STUDIES
**********
P.O.BOX 39 BAMBILI
REPUBLIQUE DU CAMEROON
Paix – Travail - Patrie
***********
UNIVERSITE DE BAMENDA
***********
ECOLE NORMALE SUPERIEURE D’ENSEIGNEMENT
TECHNIQUE
***********
DIRECTION DES ETUDES
**********
Tél: 33 05 10 69
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✓ A=1 if the candidate has at least 3 professional teaching experience years in a school in Cameroon
with a DIPET I diploma.
✓ B=1 if the candidate is fluent in English language.
✓ C=1 when the candidate is a male.
The recruitment center decides to select only males who have DIPET I diploma with at least 3 professional
teaching experience years, or who is a male and is fluent in English.
4.1) Draw the truth table of this logic function for this automatic recruitment (4 marks).
4.2) Simplify this function using Karnaugh table (4 marks)
4.3) Write this function in terms of sum of minterms (4 marks).
4.4) Draw the logic circuit using the minimum number of possible logic gates (4 marks).
Exercise 5: Simply the Boolean expressions below using.
a) A+ABC+ABC+AB (2 marks)
b) A+
BA
−−
+B (2 marks)
c) X(X+Y) (2 marks)
Exercise 6:
1. Transform the following functions only in terms of NAND gates and give the number of logic gates to be
used (4.5 marks)
𝑌 = 𝑎𝑏 + 𝑎𝑐 and 𝑆 = 𝑎𝑏 + 𝑐𝑏
2. Redo the question above by using only NOR gates (4.5 marks)
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