A bistable multivibrator, also known as a flip-flop, is a type of electronic circuit that has two stable states. It can be used to store binary information (0 or 1) and remains in one of its two states indefinitely until an external trigger, such as a voltage pulse, is applied to change its state. Because of its ability to maintain one state until switched, bistable multivibrators are fundamental in digital electronics and memory systems.

Key characteristics of bistable multivibrators:

1. Two stable states: The circuit remains in either state (high or low) until an external signal causes it to switch.

2. Memory function: It can store a bit of information, either 0 or 1, making it a basic building block for memory devices and registers.

3. Trigger input* Requires an external trigger to switch between the two states, typically through input signals like clock pulses or other logic signals.

4. Types: Common forms include SR flip-flops, JK flip-flops, D flip-flops, and T flip-flops, which differ in how the inputs control the state transitions.

These circuits are widely used in applications such as digital clocks, computers, and other devices requiring stable memory storage or state management.