JEE MainPhysicsSemiconductors
A digital logic circuit has two inputs A and B and an output Y . Over four consecutive equal time intervals, the logic levels of the inputs and the output are observed to be: Input A : 0, 1, 0, 1 Input B : 0, 0, 1, 1 Output Y : 0, 1, 0, 0 Which of the following logic circuits produces this output?
Options
- AAn AND gate whose inputs are A and B
- BAn AND gate whose inputs are A and B
- CAn OR gate whose inputs are A and B
- DAn XOR gate whose inputs are A and B
Correct answer
B. An AND gate whose inputs are A and B
Step-by-step solution
From the given data, we can construct the truth table for the circuit: A = 0, B = 0 Y = 0 A = 1, B = 0 Y = 1 A = 0, B = 1 Y = 0 A = 1, B = 1 Y = 0 We observe that the output Y is high ( 1 ) only when input A is high ( 1 ) AND input B is low ( 0 ). Therefore, the Boolean expression for the output is Y = A B . This corresponds to an AND gate which takes A and the complement of B (i.e., B ) as its inputs. Answer: An AND gate whose inputs are A and B