Flip-flops are elementary digital memory devices capable of storing a single logic state or "bit" of information. They have at least two inputs; one or more to communicate the data to be stored and another to indicate the point in time to store it. Different flip-flop types such as D (delay), SR (Set-Reset), and JK respond differently to the signals presented to their inputs and can be used to implement different logical functions. They differ from latches in that they are edge sensitive devices, whose retained logic state changes only at the moment a valid clock signal is received.
