Edgetriggered

Edgetriggered is a term used to describe a device or circuit whose state change is initiated by the transition (edge) of a signal, most commonly a clock. An edge-triggered element reacts on a specific edge, such as the rising edge or falling edge, and remains inactive for the rest of the clock cycle. This contrasts with level-triggered devices (latches) that respond to the duration of a signal being above or below a threshold.

In digital electronics, edge-triggered components are central to synchronous sequential logic. They sample inputs and update their internal state only at the clock edge, providing well-defined timing and reducing problems caused by level-sensitive gating. Edge triggering is typically implemented with a master-slave configuration of two latches or with dynamic circuit techniques, producing a flip-flop, the basic memory element in synchronous designs.

Common types include positive-edge-triggered and negative-edge-triggered flip-flops, such as D, JK, and T variants. Numerous integrated circuits, including the standard 74xx and 74HC families, implement edge-triggered flip-flops for data storage, registers, counters, and timing circuits.

Key considerations for edge-triggered devices include setup and hold times around the triggering edge, propagation delay, and susceptibility to metastability if inputs change near the clock edge. Clock quality, jitter, and noise also affect reliable operation.

In summary, edgetriggered describes a class of circuits that capture or change state in response to clock edges, enabling synchronous, predictable timing in digital systems.