Question

For the given circuit, the input digital signals are applied at the terminals A, B and C. What would be the output at the terminal y?

• A.
• B.
• C.
• D.

Answer 1

The Correct Option is C

To determine the output at terminal \( y \) for the given circuit, let's analyze the logical gates used and the input signals provided at terminals \( A \), \( B \), and \( C \).

The circuit consists of:

• Two AND gates
• One OR gate

Inputs to the gates:

• The first AND gate takes inputs from terminals \( A \) and \( B \).
• The second AND gate takes inputs from terminals \( C \) and an unspecified common input (usually \( 1 \) or always on in such gates, as typically default settings).
• The outputs of the two AND gates are then fed into an OR gate, which finally provides the output at terminal \( y \).

Given the signals:

Let's evaluate the output at each interval \( t_1 \) to \( t_6 \): 

Time	A	B	C	1st AND Output (A AND B)	2nd AND Output (C)	OR Output (y)
t1	1	0	0	0	0	0
t2	0	1	1	0	1	1
t3	1	1	0	1	0	1
t4	0	0	1	0	1	1
t5	1	1	0	1	0	1
t6	0	0	1	0	1	1

Explanation:

• During \( t_2, t_4, \) and \( t_6 \), input \( C = 1 \) causes the 2nd AND gate to output \( 1 \), ensuring \( y = 1 \) through the OR gate.
• During \( t_3 \) and \( t_5 \), inputs \( A = 1 \) and \( B = 1 \) cause the 1st AND gate to output \( 1 \), ensuring \( y = 1 \).
• At \( t_1 \), both inputs to AND gates are \( 0 \), so \( y = 0 \).

Therefore, the correct output at terminal \( y \) is: