Definition
A small, sensitive electrical switch that opens or closes a circuit with a very small physical movement of its actuator, typically used to sense position, motion, or limits in aircraft systems.
Plain English
A tiny switch that flips on or off when something pushes against it just slightly. Aircraft use them to detect when a part has moved into a certain position — like when a landing gear is fully down or a flap has reached its limit.
Context Anchor
Seen in aircraft electrical systems, landing gear systems, door and latch warning systems, and maintenance troubleshooting.
Derivation
From 'micro' (Greek mikros, meaning small) and 'switch.' The 'micro' refers to the very small movement needed to operate it — not to the switch's physical size, though they are usually small too.
Why Pilots Care
Reliable microswitches ensure accurate cockpit indications for critical systems like gear position without adding weight or bulk.
Analogy
Like the small button inside a refrigerator door that turns the light off the moment the door closes — a tiny push on the button is all it takes.
Intuition Check
Do not read microswitch as a computer or electronic chip. It is usually a small physical switch that is pressed or released by a moving aircraft part.
Example Sentence 1
When the landing gear reaches the fully extended position, a microswitch closes the circuit and illuminates the green gear-down light in the cockpit.
Example Sentence 2
A sticking microswitch in the baggage door caused a false warning light during the preflight check.