Identify the gate that outputs the complement of its single input (i.e., logical inversion): Which basic logic gate performs this operation?

Introduction / Context:
Digital systems often need the logical complement of a signal for control, timing, and active-low conventions. The device that provides this complement is fundamental and appears in virtually every logic family and integrated function block.

Given Data / Assumptions:

• Single-input, single-output logic function.
• Output equals NOT(input).
• Ideal logic levels are assumed.

Concept / Approach:
The NOT operation maps 0 → 1 and 1 → 0. The simplest gate implementing NOT is called an inverter (sometimes labeled as a NOT gate or 7404 in TTL for a hex inverter). It is distinct from comparators, which are analog-level thresholding devices that produce logic-level outputs but are not simple NOT functions of a single logic input.

Step-by-Step Solution:

Verification / Alternative check:
Truth table for an inverter: X=0 → Y=1; X=1 → Y=0. Other gates (AND, OR) require two or more inputs and do not invert a single input by themselves.

Why Other Options Are Wrong:

• OR / AND: Multi-input gates that do not invert a single input.
• Comparator: Analog threshold device; output depends on analog difference relative to a reference, not merely the logical complement of a logic input.

Common Pitfalls:
Assuming a comparator is a digital NOT because it outputs logic levels—its function and use cases are different (windowing, thresholding, Schmitt triggering).

Final Answer:
INVERTER gate