Difficulty: Easy
Correct Answer: Correct
Explanation:
Introduction / Context:Logic gate identities are foundational. This item checks whether learners recognize that a 2-input AND with one input tied HIGH acts as a buffer (passes the other input unchanged).
Given Data / Assumptions:
Concept / Approach:If Y = A * B and A = 1, then Y = 1 * B = B. The gate becomes a conditional pass-through for B. This is a basic Boolean identity and underlies many enable/disable designs (an AND as an enable gate).
Step-by-Step Solution:
Start with Y = A * B.Fix A = 1 (HIGH).Compute Y = 1 * B = B.Therefore, the output reflects the other input.Verification / Alternative check:Truth table inspection with A = 1: If B = 0 → Y = 0; if B = 1 → Y = 1. Output equals B in all cases.
Why Other Options Are Wrong:
Incorrect / negative-logic qualifiers: The identity is true in standard positive logic; NAND or negative logic changes the function.Frequency qualifier: Logical identity is independent of clock rate (assuming proper timing and no hazards).Common Pitfalls:Confusing AND with OR (where tying one input HIGH forces HIGH). Mixing up AND and NAND effects.
Final Answer:Correct
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