Negative logic convention: In a negative-logic system, which voltage region corresponds to a logical HIGH (logic 1) level?

Introduction / Context:
Digital systems can define logic levels using either positive or negative logic conventions. In positive logic, a higher voltage represents logic 1; in negative logic, the mapping is inverted. This question ensures clarity about what “logic HIGH” means under negative logic.

Given Data / Assumptions:

• Two-level digital system with defined valid LOW and HIGH voltage regions.
• Negative logic definition: logic 1 is assigned to the lower voltage region.
• We identify which voltage region corresponds to logical HIGH (logic 1) in negative logic.

Concept / Approach:
Logic conventions are labelings applied to the same physical voltage windows. Negative logic simply swaps the semantic labels: low voltage corresponds to logic 1 (HIGH), and high voltage corresponds to logic 0 (LOW). The electronics do not change; only the interpretation does.

Step-by-Step Solution:

Verification / Alternative check:
Truth tables can be reinterpreted by swapping labels; hardware remains identical while logical naming changes, confirming the mapping.

Why Other Options Are Wrong:
HIGH: that is the positive-logic mapping, not negative logic.

off: not a standard logic-level designation; ambiguous.

uncertain: implies the indeterminate region, not a defined logic level.

Common Pitfalls:
Equating “HIGH” with “high voltage” universally; always check whether the system uses positive or negative logic before labeling signals.

Final Answer:
LOW