- one complete convolution of a conducting coil, through which one ampere of current passes.
- the magnetomotive force produced by one ampere passing through one complete turn or convolution of a coil. Abbreviation: At
- a unit of magnetomotive force; the magnetomotive force produced by a current of 1 ampere passing through one complete turn of a coil. 1 ampere-turn is equivalent to 4π/10 or 1.257 gilbertsAbbreviation: At, A