Definition
A unit of magnetomotive force equal to the magnetizing effect produced by a current of one ampere flowing through one turn of a coil of wire. The total magnetomotive force of a coil is found by multiplying the current in amperes by the number of turns in the coil.
Plain English
A way of measuring how much magnetic push a coil of wire creates. You get the number by multiplying how much current is flowing through the wire by how many times the wire is wrapped around the coil.
Context Anchor
Seen in aircraft electrical theory, especially when discussing coils, relays, solenoids, generators, alternators, and motors.
Derivation
The name comes directly from the two things being multiplied: amperes (the unit of electric current, named after French physicist André-Marie Ampère) and turns (the loops of wire in a coil). The term itself describes the calculation.
Why Pilots Care
Determines the strength of electromagnets used in aircraft magnetos, relays, and actuators.
Analogy
It is like wrapping a rope around a post and pulling. One wrap with a light pull has less effect than many wraps or a stronger pull; in a coil, the wraps are turns of wire and the pull is electric current.
Intuition Check
Turn does not mean an aircraft turn here. It means one complete loop of wire in a coil.
Example Sentence 1
A solenoid with more ampere-turns produces a stronger magnetic field, allowing it to pull its plunger with greater force.
Example Sentence 2
Technicians checked the ampere-turns in the solenoid to ensure reliable landing gear operation.