## Logic-Gates

 Question 1
Let and denote the Exclusive OR and Exclusive NOR operations, respectively. Which one of the following is NOT CORRECT?
 A B C D Digital-Logic-Design       Logic-Gates       Gate 2018
Question 1 Explanation: Question 2
Which one of the following circuits is NOT equivalent to a 2-input XNOR (exclusive NOR) gate?
 A B C D Digital-Logic-Design       Logic-Gates       Gate 2011
Question 2 Explanation:
All options except option ‘D’ gives EX-NOR gates
 Question 3
 A B C D Digital-Logic-Design       Logic-Gates       2010
Question 3 Explanation:
f = ((P’Q’ + Q’R’)’ + ( P’R’ + Q’R’)’ )’
= (P’Q’ + Q’R’)( P’R’ + Q’R’)
= (P’Q’P’R’ + P’Q’Q’R’ + Q’R’P’R’ + Q’R’Q’R’)
= (P’Q’R’ + P’Q’R’ + P’Q’R’ + Q’R’)
= (P’Q’R’ + Q’R’)
= (Q’R’)
= (Q+R)’
 Question 4
What is the minimum number of gates required to implement the Boolean function (AB+C) if we have to use only 2-input NOR gates?
 A 2 B 3 C 4 D 5
Digital-Logic-Design       Logic-Gates       2009
Question 4 Explanation:
NOR is Complement of OR
AB+C
= (A+C)(B+C) ← Distribution of + over
= ((A+C)’+(B+C)’)’
1st NOR- (A+C)’. Let X = (A+C)’
2nd NOR- (B+C)’. Let Y = (B+C)’
3rd NOR- (X+Y)’
 Question 5
What is the minimum number of NAND gates required to implement a 2-input EXCLUSIVE-OR function without using any other logic gate?
 A 3 B 4 C 5 D 6
Digital-Logic-Design       Logic-Gates       Gate 2004-IT
Question 5 Explanation: To create 2-input Exclusive-OR function we require 4 NAND gates.
 Question 6
 A 1 B 2 C 3 D 4
Digital-Logic-Design       Logic-Gates       Gate-2003
Question 6 Explanation: ⇒ a will always be equal to A. Question 7
 A x NAND X B x NOR x C x NAND 1 D x NOR 1
Digital-Logic-Design       Logic-Gates       Gate-1999
Question 7 Explanation: Question 8
 A A = 0, B = 0, C = 1 B A = 0, B = 1, C = 1 C A = 1, B = 0, C = 1 D A = 1, B = 1, C = 1
Database-Management-System       Logic-Gates       Gate-1999
Question 8 Explanation: So the above equation is satisfied if either C=0 or A=0 and B=1.
Hence, Option (B) is correct.
 Question 9
Which of the following operations is commutative but not associative?
 A AND B OR C NAND D EXOR
Digital-Logic-Design       Logic-Gates       Gate-1998
Question 9 Explanation:
NAND operation is commutative but not associative.
 Question 10
 A B C D E None of the above.
Digital-Logic-Design       Logic-Gates       Gate-1994
Question 10 Explanation: Question 11
 A exclusive OR B exclusive NOR C NAND D NOR E None of the above
Digital-Logic-Design       Logic-Gates       Gate-1993
Question 11 Explanation: So finally, we can write There are 11 questions to complete.