JK Flip-flop

Has 2 inputs: and , and 1 output: . Invalid state of SR flip-flop is eliminated here.

• When J = 0 and K = 0, the output Q remains unchanged (no change state).
• When J = 0 and K = 1, the output Q is reset to 0 (reset state).
• When J = 1 and K = 0, the output Q is set to 1 (set state).
• When J = 1 and K = 1, the output Q toggles its state (toggle state).

The JK flipflop is widely used in digital systems for counters, shift registers, and other applications where toggling or controlled state changes are required.

Excitation table

Current State (Q)	Next State (Q+)	J	K
0	0	0	X
0	1	1	X
1	0	X	1
1	1	X	0