Combinational Logic Analysis - Technical MCQs

Q1:

The 8-input XOR circuit shown has an output of Y = 1. Which input combination below (ordered A – H) is correct?

A 10111100

B 10111000

C 11100111

D 00011101

ANS:A - 10111100

Option A = 10 11 11 00

A XOR B = 1 XOR 0 => 1
C XOR D = 1 XOR 1 => 0

E XOR F = 1 XOR 1 => 0
G XOR H = 0 XOR 0 => 0

(A XOR B) XOR (C XOR D) = 1 XOR 0 => 1 .....(1)
(E XOR F) XOR (G XOR H) = 0 XOR 0 => 0 .....(2)

(1) XOR (2) = 1 XOR 0 => 1.

Hence the Option A is correct.