Question

One of the following values of inputs A, B and C respectively gives output (Y) of the following combination of logic gates as '1' is \dots

• A. 0, 0, 0
• B. 0, 1, 0
• C. 1, 0, 0
• D. 1, 0, 1

Hint:

To solve logic gate problems quickly, work backward from the required output! If the final gate is an AND gate requiring a '1' output, you instantly know every single wire feeding into it MUST carry a '1'.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Logic gates process binary inputs (0 or 1). We must trace the inputs through the specific gates (AND, OR, NOT, etc.) to find the resulting output.

Step 2: Formula Application:
Let's assume the gate is $(A \cdot B) + C = Y$ or $(A + B) \cdot C = Y$. In most common exam diagrams for this specific question, the final gate is an OR gate receiving input from an AND gate (A, B) and a direct line C.

Step 3: Explanation:
If $Y = (A \text{ AND } B) \text{ OR } C$, then if $C = 1$, the output $Y$ will always be 1 regardless of A and B. Checking Option D: $A=1, B=0, C=1 \implies (1 \cdot 0) + 1 = 0 + 1 = 1$.

Step 4: Final Answer:
Input values 1, 0, 1 give an output of 1.