- A versatile flip-flop whose inputs are designated as J and K, along with a clock input. Such a flip-flop has no undefined states, no race condition, and is edge triggered. If both the J and K inputs are at logic 1 when the clock pulse arrives, it toggles between states. If the J and K inputs are at logic 0 when the clock pulse arrives, there is no change. If J is at logic 1 and K at logic 0, a clock pulse drives the output to 1, and if J is at logic 0 and K at logic 1, a clock pulse drives the output to 0. Its abbreviation is JKFF.