NEETPhysicsSemiconductors
Consider a digital logic circuit with two inputs A and B , and an output Y . The timing diagrams for the inputs and output show the following logic levels across four consecutive time intervals: Input A : 0, 1, 0, 1 Input B : 0, 0, 1, 1 Output Y : 1, 0, 0, 0 Which of the following logic circuit configurations produces this output?
Options
- AInputs A and B are fed directly into an AND gate.
- BInputs A and B are fed directly into an OR gate.
- CInput A is fed to a NOT gate, input B is fed to a NOT gate, and their outputs are fed into an OR gate.
- DInput A is fed to a NOT gate, input B is fed to a NOT gate, and their outputs are fed into an AND gate.
Correct answer
D. Input A is fed to a NOT gate, input B is fed to a NOT gate, and their outputs are fed into an AND gate.
Step-by-step solution
From the given logic levels across the four time intervals, we can construct the truth table for the circuit: Interval 1: A = 0, B = 0 Y = 1 Interval 2: A = 1, B = 0 Y = 0 Interval 3: A = 0, B = 1 Y = 0 Interval 4: A = 1, B = 1 Y = 0 This truth table corresponds to the NOR logic operation, where the output is high only when both inputs are low. The Boolean expression for a NOR gate is Y = A + B . According to De Morgan's laws, A + B = A B . This expression represents taking the complement of A (using a NOT gate), t