Pulse-Triggered (Master-Slave) Flip-flops
Data Lock-Out Flip-flops
Flip-flops are synchronous bistable devices. The term synchronous means the output changes state only when the clock input is triggered. That is, changes in the output occur in synchronization with the clock.
Flip-flop is a kind of multivibrator. There are three types of multivibrators:
- Monostable multivibrator (also called one-shot) has only one stable state. It produces a single pulse in response to a triggering input.
- Bistable multivibrator exhibits two stable states. It is able to retain the two SET and RESET states indefinitely. It is commonly used as a basic building block for counters, registers and memories.
- Astable multivibrator has no stable state at all. It is used primarily as an oscillator to generate periodic pulse waveforms for timing purposes.
In this tutorial, the three basic categories of bistable elements are emphasized: edge-triggered flip-flop, pulse-triggered (master-slave) flip-flop, and data lock-out flip-flop. Their operating characteristics and basic applications will also be discussed.