Logic design terminology: Which gate is known as a “universal gate” because it can be combined to implement any Boolean function (including AND, OR, and NOT)?

Introduction / Context:
Universal gates are building blocks from which any logic function can be constructed without needing other gate types. Recognizing them helps in cost-optimized designs, minimization, and standardizing on a small set of parts in hardware.

Given Data / Assumptions:

• The question asks specifically for a gate that can implement any Boolean function.
• We consider standard families and functional completeness.
• Practical gate composition is allowed (multiple devices as needed).

Concept / Approach:
A functionally complete set of gates can realize all Boolean expressions. A single gate type is “universal” if repeated use of that one type can produce AND, OR, and NOT. NAND is universal because you can create NOT by tying its inputs together, AND by inverting the output of a NAND, and OR by applying De Morgan’s law with inverted inputs.

Step-by-Step Solution:
NOT from NAND: NAND(A, A) = NOT(A).AND from NAND: AND(A, B) = NOT(NAND(A, B)) = NAND(NAND(A, B), NAND(A, B)).OR from NAND via De Morgan: OR(A, B) = NOT(AND(NOT A, NOT B)) = NAND(NAND(A, A), NAND(B, B)).Hence, any expression composed of AND/OR/NOT can be built from NANDs.

Verification / Alternative check:
NOR is also universal, but the question asks for the gate “known as” a universal gate—NAND is the most commonly cited example in course material and component catalogs.

Why Other Options Are Wrong:
NOT: alone cannot compose both AND and OR.AND: cannot invert by itself.XOR: not functionally complete alone.None of the above: incorrect, because NAND is universal.

Common Pitfalls:
Thinking XOR is universal due to its usefulness in adders; it still needs inversion and other operations to be complete.

Final Answer:
NAND gate