Flip‑Flops & Sequential Logic — A/L Physics

Sequential Logic Circuit A circuit whose output depends on both current inputs and the past sequence of inputs (i.e., it has memory). Unlike combinational logic, sequential circuits store state using feedback. The output is a function of present inputs and the internal state (history). Example: a digital counter that remembers the last count.

Flip‑Flop (Bistable Multivibrator) A fundamental 1‑bit memory element that has two stable states (0 or 1) and changes state only on a clock edge or control signal. Flip‑flops are edge‑triggered (unlike latches, which are level‑sensitive). They form the building blocks of registers, counters, and finite state machines. Example: a D flip‑flop stores a single data bit until the next clock edge.