Question

The following figure shows a logic gate circuit with two inputs \(A\) and \(B\) and the output \(Y\). The voltage waveforms of \(A, B\) and \(Y\) are as given. The logic gate is

• A. NOR gate
• B. OR gate
• C. AND gate
• D. NAND gate

Answer 1

The Correct Option is D

To determine the logic gate type, we need to analyze the waveforms of inputs \( A \) and \( B \), and the output \( Y \). The circuit's truth table provides key insights into its behavior: 

\( A \)	\( B \)	\( Y \)
0	0	1
0	1	1
1	0	1
1	1	0

The observed waveform behavior corresponds to the truth table of a NAND gate. In a NAND gate, the output is low (0) only when both inputs are high (1). Otherwise, the output remains high (1).

Below is the waveform image supporting this analysis:

Let’s rule out the other options:

1. NOR Gate: Produces a high output only when both inputs are low, which doesn't match our table.
2. OR Gate: Produces a high output when at least one input is high.
3. AND Gate: Produces a high output only when both inputs are high.

Given the waveform and truth table match, the logic gate in question is confirmed to be a NAND gate.