Definition
An electronic circuit with two stable output states that holds whichever state it was last switched into until an input pulse flips it to the other state. Because it stores one bit of information until told to change, it is widely used as a memory element and as a frequency divider in digital electronics. Also called a flip-flop.
Plain English
A small electronic circuit that has two settled states — call them on and off — and stays in whichever one it is in until a signal tells it to switch. It remembers its state, so it acts like a one-bit memory.
Context Anchor
Seen in avionics, autopilot, radio, and electronic equipment descriptions, especially when a circuit must remember a selected condition or switch between two choices.
Derivation
From Latin 'bi-' meaning two, and 'stabilis' meaning steady or stable — so 'bistable' means having two stable states. 'Multivibrator' was coined for a class of circuits that can produce or switch between multiple voltage levels. Together: a multi-state switching circuit that has two stable resting points.
Why Pilots Care
Pilots do not operate these circuits directly, but they are the building blocks of digital avionics — every digital counter, memory bit, and logic stage in modern instruments relies on them. Knowing the term helps when reading avionics theory or troubleshooting documentation.
Analogy
Think of a household light switch. It rests in either up or down, and it stays there until something physically flips it. A bistable multivibrator is the electronic version of that switch.
Intuition Check
Do not picture a part that physically vibrates. In this term, “multivibrator” means an electronic circuit that changes electrical states, not a moving mechanical device.
Example Sentence 1
The avionics technician explained that the digital counter inside the instrument was built from a chain of bistable multivibrators, each one storing a single bit.
Example Sentence 2
Maintenance checks the bistable multivibrator to confirm it holds each state reliably during power cycles.