- an instrument for measuring inductance, consisting essentially of an inductor with two or more coils whose relative position may be changed to vary the inductance.
- an instrument for indicating a change in a component of a magnetic field vector, especially one related to the earth's magnetic field.
- an instrument that indicates the rate of climb or descent.
- an instrument for measuring variations in a magnetic field, used esp for studying the magnetic field of the earth
- a variable inductor consisting of a movable coil mounted inside and connected in series with a fixed coil
- a sensitive rate-of-climb indicator, used mainly in gliders
