Edge-triggered flip-flops — essential requirement Which statement best captures what an edge-triggered flip-flop must include to detect and respond to clock transitions?

Introduction / Context:
Edge-triggered flip-flops change state only at a clock transition, not during the level between edges. This behavior relies on internal circuitry that senses a rising or falling clock edge and briefly opens a sampling window.

Given Data / Assumptions:

• Generic edge-triggered D/JK flip-flops.
• Device may be positive-edge or negative-edge triggered.

Concept / Approach:
The essential feature is an internal edge-detection mechanism (often implemented with transmission gates, pulse generators, or master–slave structures) that creates a short sampling pulse when the clock transitions. Whether the device is positive- or negative-edge triggered depends on the specific design, but all such flip-flops must detect an edge.

Step-by-Step Reasoning:

Verification / Alternative check:
Master–slave implementations effectively sample on one level and transfer on the next, emulating edge sensitivity; pulse-triggered designs explicitly generate a narrow pulse at the clock edge. Both embody edge detection internally.

Why Other Options Are Wrong:

• Very fast response times: useful but not the defining requirement.
• Two inputs for rising and falling edges: a single clock input suffices; the device is designed for one edge.
• Positive-only / Negative-only: devices can be either; saying “only” is too restrictive.

Common Pitfalls:

• Assuming edge-triggered means faster; it actually means edge-qualified sampling.

Final Answer:
an internal edge-detection network for clock transitions (either positive or negative edge)