In basic logic design, which gate with two or more inputs produces a high (logic 1) output only when all of its inputs are high?

Introduction / Context:
The fundamental Boolean gates—AND, OR, and NOT—form the foundation of digital logic. Knowing exactly how each gate responds to combinations of inputs is essential for building combinational circuits such as decoders, comparators, and arithmetic units. This item checks whether you can map a verbal specification (“high only when all inputs are high”) to the correct gate behavior.

Given Data / Assumptions:

• The gate accepts two or more input signals.
• The output should be high only if every input is high.
• We use standard positive logic (high = 1, low = 0).

Concept / Approach:
By definition, the AND operation returns 1 if and only if all inputs are 1. Any input at 0 forces the output to 0. This matches exactly the phrasing “high only when all inputs are high.” OR, NAND, and NOR have different truth conditions that do not match the specification.

Step-by-Step Solution:
Recall truth condition: AND outputs 1 only for the all-ones input combination.Compare: OR outputs 1 if any input is 1; NOR and NAND involve inversion.Select the gate matching the described behavior: AND.

Verification / Alternative check:
Truth table check for two inputs A and B: AND gives 1 only for A=1 and B=1. For three or more inputs, the same rule generalizes—every input must be 1 to get a 1 at the output.

Why Other Options Are Wrong:
OR: outputs high if at least one input is high, not all.NAND: outputs the complement of AND (low only when all inputs are high).NOR: outputs 1 only when all inputs are low, the opposite extreme.None of the above: incorrect because AND fits perfectly.

Common Pitfalls:
Confusing “any” with “all,” and mixing up NAND with AND. Also, overlooking that multi-input versions follow the same rule as two-input gates.

Final Answer:
AND