Undefined logic condition terminology An input or node that is neither driven to a valid logic HIGH nor to a valid logic LOW is best described as which state?

Introduction / Context:
Digital circuits rely on clearly defined voltage levels to represent logic 0 and logic 1. When a node is not actively driven or properly biased, its voltage can wander, pick up interference, or sit at an indeterminate level. Recognizing and naming this condition is crucial to robust design and debugging.

Given Data / Assumptions:

• A logic input is left unconnected (no pull-up/pull-down) or an output stage is high-impedance without external bias.
• Standard logic families expect finite source/sink paths to set valid thresholds.
• Terminology should reflect the electrical condition, not a design-time notation.

Concept / Approach:
When a digital node is undriven, it is “floating.” A floating input can drift due to leakage and capacitive coupling, leading to unpredictable switching and power consumption. Designers prevent floating states with bias networks (pull-ups/pull-downs), keeper circuits, or by ensuring every input is tied to a defined level.

Step-by-Step Solution:

Verification / Alternative check:
Oscilloscope traces of floating nodes show random or slow drift; data sheets warn against leaving CMOS inputs floating due to shoot-through current and oscillation.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming “high impedance” equals “safe.” High-Z outputs still need external biasing on shared lines to avoid floating receivers.

Final Answer:
floating