Customized High Quality Electric Winding Air Core Coil Inductor

 What is an air core inductor?

Air core inductors represent a fascinating class of electronic components that are unique in their design and functionality. The key to air core inductors (literally) is the avoidance of using magnetic material in the center region of the inductor coil. Instead, it uses free space – air – as the magnetic core. Since air is classified as a non-magnetic material, this puts air core inductors firmly in the category of non-magnetic core inductors.

Unique design and principle

The defining characteristic of an air-core inductor is its construction. Unlike magnetic core inductors, which are able to store and amplify magnetic flux, air-core inductors rely on the inherent inductive properties of the coil itself and the air around it. A magnetic field is generated when current flows through the coil, but without the influence of the magnetic core, that field behaves significantly differently. This fundamental design choice determines its performance attributes and application scenarios.

Performance characteristics

One of the most significant advantages of air-core inductors is their lack of core losses. Hysteresis losses (which occur when a magnetic material is repeatedly magnetized and demagnetized, dissipating energy in the process) and eddy current losses (which occur when current circulates inside the magnetic core) are absent in air-core inductors. No losses means higher efficiency, especially in high-frequency applications.

However, there are some drawbacks to this design. Since the magnetic permeability of air is very low compared to magnetic materials, the inductance value of air core inductors is usually relatively low. In order to compensate and obtain a larger inductance, it is usually necessary to increase the number of turns of the inductor coil. This in turn requires a higher magnetomotive force (MMF) to drive the current through the increased number of turns.

Circuit Symbols

The circuit symbol for air-core inductors, shown in Figure 1, visually demonstrates their uniqueness in electrical schematics. This symbol helps engineers and designers quickly identify air-core inductors and incorporate them into circuit designs, thereby facilitating the creation of innovative and efficient electrical systems.