In a typical digital logic family, if Logic 0 spans 0 to 0.8 V, what voltage range is recognized as a valid Logic 1 level?

Introduction:
Digital logic families define voltage thresholds for interpreting signals as Logic 0 (LOW) or Logic 1 (HIGH). Knowing these ranges ensures reliable interfacing and noise immunity.

Given Data / Assumptions:

• Logic 0 (LOW) range: 0 to 0.8 V.
• We need the corresponding Logic 1 (HIGH) range in a typical 5 V logic system.
• Assume standard TTL-like thresholds where VIH(min) is near 2.0 V.

Concept / Approach:
Classic TTL specifies VIL(max) around 0.8 V and VIH(min) around 2.0 V, with VCC near 5 V. Thus, valid HIGH levels are typically any voltage from roughly 2.0 V up to VCC (about 5 V).

Step-by-Step Solution:

Verification / Alternative check:
CMOS families at 5 V often use fractions of VCC, but TTL-compatibility commonly accepts ≥ 2.0 V as HIGH in mixed systems; 2–5V remains the broadly correct range here.

Why Other Options Are Wrong:

• 2.5–5V: Too restrictive; 2.1 V or 2.2 V should still be HIGH in TTL-compatible inputs.
• 3.0–5.5V and 3.5–5.5V: Unrealistically high VIH(min); excludes valid HIGHs between 2 and 3 V.

Common Pitfalls:
Assuming all families use identical thresholds; always consult the specific datasheet. However, the 2–5 V convention remains a widely taught baseline for TTL levels.

Final Answer:
2–5V