Digital Electronics - Combinational Logic Circuits - Discussion


The binary numbers A = 1100 and B = 1001 are applied to the inputs of a comparator. What are the output levels?

[A]. A > B = 1, 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 = 1, A = B = 1

Answer: Option C


No answer description available for this question.

Xyz said: (May 3, 2011)  
Please someone explain this logic.

Selva said: (Dec 3, 2011)  
I can't understand the logic in a given options.

Please any one explain me the logic.

Adarsha.Barkua said: (Feb 18, 2012)  
A=1100 AND B=1001
SO both having equal number of one's and zero's but the value is differs. A is greater compare to B but it's having equal no of one's (A>B=1) same holes good for next statement but considering zero's A value is smaller compare to B but its having equal number of zero's (A<B=0) and finally both are equal (A=B=0) zero indicate hr (A-B) but in the form of number of ones and zero's present both are equal so zero.

Sudeep said: (May 21, 2012)  
As far I am thinking its a comparator which compares two numbers.
A is 1100 (12) , B is 1001 (9). A>B (TRUE so 1) , A<B (FALSE so 0) , A=B (FALSE so 0).

Well I am not sure whether I am following the correct logic.

Chandan said: (Aug 31, 2012)  
Yes, sudeep give correct explanation.

Sanjiya said: (Apr 1, 2013)  
A = 1100,(12).
B = 1001,(9).

1 is represent true.
0 is represent false.

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

True, False, False.

Judepraveen said: (Dec 16, 2014)  
What is the correct answer?

Manowar said: (Aug 7, 2016)  
You are right @Sudeep.

Divya Chaudhary said: (Nov 4, 2016)  
The logic behind the ansswer is:

There can be three cases : number A is greater than number B,or less than B or equal to B.

Now,in question A=1100 whose decimal equivalent is 12 and B=1001 whose binary equivalent is 9.

So case1 is true, and we are using 1 for true and 0 for combining three cases to giveanswer we get,

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

Vanitha said: (May 27, 2017)  
Thanks for your explanation @Sanjiya.

Sachin said: (Aug 17, 2017)  
You give a simple explanation easy to understand. Thanks @Sudeep.

Shaik said: (Sep 21, 2017)  
You are right, thanks for the explanation @Sudeep.

Manogna said: (Feb 20, 2018)  
I am not getting the solution. Anyone help me to get it.

Vishaka said: (Feb 21, 2018)  
It's a bitwise comparison so A=B=1 , A>B=1,A<B=0.
according to my knowledge,

1st-row A=B, 2nd-row A>B, 3rd-row A=B, 4th-row A=B.

E is equal, G is greater.

Kanmani said: (May 2, 2019)  
Thanks @Sudeep.

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