Question

The output of the circuit is low (zero) for:

(A) \( X = 0, Y = 0 \) 
(B) \( X = 0, Y = 1 \) 
(C) \( X = 1, Y = 0 \) 
(D) \( X = 1, Y = 1 \) 
Choose the correct answer from the options given below:

• A. (A), (B) and (C) only
• B. (B), (C) and (D) only
• C. (A), (C) and (D) only
• D. (A), (B) and (D) only

Hint:

In an AND gate, the output is 1 only when both inputs are 1. In an OR gate, the output is 1 if at least one input is 1. Consider these truth tables when analyzing circuits.

Answer 1

The Correct Option is A

The circuit comprises two logic gates: an AND gate and an OR gate. The output is evaluated for each input pair \( X \) and \( Y \):

• For \( X = 0, Y = 0 \): The AND gate outputs \( 0 \). The OR gate outputs \( 0 \). The final output is \( 0 \).
• For \( X = 0, Y = 1 \): The AND gate outputs \( 0 \). The OR gate outputs \( 1 \). The final output is \( 0 \).
• For \( X = 1, Y = 0 \): The AND gate outputs \( 0 \). The OR gate outputs \( 1 \). The final output is \( 0 \).
• For \( X = 1, Y = 1 \): The AND gate outputs \( 1 \). The OR gate outputs \( 1 \). The final output is \( 1 \).

The output is low for the following input combinations:

• (A) \( X = 0, Y = 0 \)
• (B) \( X = 0, Y = 1 \)
• (C) \( X = 1, Y = 0 \)

Final Answer: (1) (A), (B), and (C) only.