Self-supporting air core coil wound in round copper or aluminium. With no core there is nothing to saturate and no core loss, so inductance holds constant with current — which is why they persist in RF and crossover work.
Outline of Air Core Inductor / Round Wire, drawn from its published specification.
1CoreAir
2MountingThrough-hole
3OrientationHorizontal
Construction
Copper or Aluminium Round Wire, Self-Supporting
Configuration · Round Wire
Linearity
No core, nothing to saturate
Give up the permeability a core provides and you get something a ferrite part cannot offer at any price: inductance that does not change with current, and no core loss at frequency.
Inductance
Current
Air core — flat to the thermal limit
Ferrite core — saturates
Inductance holds from zero current to the thermal limit. There is no core, so there is nothing to saturate and nothing to move with temperature.
No core loss either, so Q stays high at frequency where a ferrite of the same value would be heating.
The cost is permeability. An air core needs far more turns for the same inductance, so it is physically larger — which is why it is specified where linearity matters more than size.
Air core against a ferrite core of the same nominal value
Specification
Published figures describe the standard build. Every part is wound to order — send your exact requirement and we will confirm the specification on the quotation.
Core
Air
Winding
Round Copper / Aluminium
Inductance
0.05uH - 100uH
Tolerance
+/-5% typical
Application
RF, Audio Crossovers, Filters
Typical applications
Air core inductors for high-frequency and high-linearity applications where core saturation and core loss cannot be tolerated.