Question

A logic gate circuit has two inputs A and B and output Y. The voltage waveforms of A, B and Y are shown below.
 

Fig. Logic gate circuit

The logic gate circuit is :

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

Answer 1

The Correct Option is A

To determine the logic gate circuit, we need to analyze the given voltage waveforms for inputs A, B, and output Y:

Fig. Logic gate circuit 

From the waveform:

1. Observe when both inputs A and B are high (1), the output Y is also high (1).
2. When either A or B is low (0), the output Y is low (0).

This behavior is consistent with an AND gate, which outputs high only when all its inputs are high.

Verification Against Options:

• AND gate: Matches the observed behavior (correct).
• OR gate: Would output high if any input is high (does not match).
• NOR gate: Inverse of OR gate, would output low if any input is high (does not match).
• NAND gate: Inverse of AND gate, would output low only if all inputs are high (does not match).

Therefore, the logic gate circuit is indeed an AND gate.

Answer 2

The correct answer is (A) : AND gate
On the basis of given graph, following table is possible.

A	B	C
0	0	0
1	1	1
0	1	0
1	0	0

From waveforms and above table, it is an AND gate.