JKFlipFlop

A JK flip-flop is a type of digital storage element that stores one bit of information and changes state on a clock edge. It has two data inputs, labeled J and K, and two outputs, Q and Q'. The JK is a universal flip-flop because, depending on J and K, it can perform the functions of a set, reset, hold, and toggle.

On a triggering clock edge (positive-edge or negative-edge, depending on design), the next state Q+ is determined as follows: if J=0 and K=0, Q+ = Q (no change); if J=0 and K=1, Q+ = 0 (reset); if J=1 and K=0, Q+ = 1 (set); if J=1 and K=1, Q+ = not Q (toggle). The toggle behavior on J=K=1 makes JK flip-flops useful for building counters.

In practice JK flip-flops are implemented as edge-triggered devices, often as master-slave latches or via other gating to ensure changes occur only on the clock edge. Many devices include asynchronous preset and clear inputs for immediate forcing of Q or Q'. They may be positive-edge-triggered or negative-edge-triggered.

Applications include binary counters, frequency dividers, and shift-register configurations. They are commonly found in digital integrated circuits and textbooks as a flexible alternative to SR and D flip-flops.

Related devices include SR flip-flops, D flip-flops, and T flip-flops.