Definition
A method of slowing or stabilizing the motion of a moving instrument component by using small circulating electrical currents (eddy currents) that are induced when a conductive disc or vane moves through a magnetic field. The induced currents create a magnetic drag that opposes the motion, smoothing out oscillations without using friction or springs.
Plain English
It is a way of calming down a moving needle or pointer in an instrument by letting a magnet quietly drag on it, so it settles to a steady reading instead of swinging back and forth.
Context Anchor
Seen in aircraft instrument construction and maintenance, especially when explaining how mechanical instrument pointers are kept steady.
Derivation
An 'eddy' is a small swirling motion, like a whirlpool in water. The term was borrowed for electricity because the induced currents swirl in small loops inside the metal. 'Damping' comes from an older sense of 'damp' meaning to deaden or muffle — the same idea as damping a vibrating string. Together: tiny swirling currents that quietly muffle motion.
Why Pilots Care
Prevents instrument needles from oscillating, delivering steady and readable indications essential for accurate flight data.
Analogy
Imagine sliding a metal plate past a strong magnet — even though they never touch, you feel a smooth resistance. That invisible drag is what steadies an instrument needle.
Intuition Check
Do not read “current” as airflow or present time here. In this term, “current” means electric current, and “damping” means reducing unwanted motion, not making something wet.
Example Sentence 1
The vertical speed indicator uses eddy current damping to keep the needle from bouncing during minor turbulence.
Example Sentence 2
Eddy current damping keeps the ammeter pointer from swinging wildly when current flow changes rapidly.