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Code Converters and Multiplexers - Technical MCQs

Q1:

For the following conditions on a 7485 magnitude comparator, what will be the state of each of the three outputs?
A0 = 0B0 = 1IA < B = 0
A1 = 1B1 = 0IA = B = 1
A2 = 1B2 = 0IA > B = 0
A3 = 0B3 = 0 

A A = B = 0, A < B = 0, A > B = 1

B A = B = 0, A < B = 1, A > B = 0

C A = B = 1, A < B = 0, A > B = 0

D A = B = 0, A < B = 0, A > B = 0

ANS:A - A = B = 0, A < B = 0, A > B = 1

i.e 15 14 13 12 ...................................... 1 0
The LSB (least significant bit) is 0.
MSB (most significant bit ) is 15.

So,
A3 A2 A1 A0 => 0110
B3 B2 B1 B0=> 0001

The decimal Values for A is 6 & B is 1

Now compare for each state.

State 1: A=B
=> No A!=B(A is not equal to B)
=> So, A=B=0

State 2: A<B
=> No A!<B(A is not less than B)
=> So, A<B=0 ()

State 3: A>B
=> A>B(A is greater than B)
=> So, A>B=1 (6>1)

Therefore option (A) is correct.