Test & measurement
Air core coils are suitable for passive crossover networks that do not need a ferromagnetic material to meet their inductance parameters. They are, for physical reasons, superior to all metal-core coils as far as accurate pulse reproduc Show more
Air core coils are suitable for passive crossover networks that do not need a ferromagnetic material to meet their inductance parameters. They are, for physical reasons, superior to all metal-core coils as far as accurate pulse reproduction and freedom from distortion are concerned. They can be used in various applications, such as a middle-frequency high-pass filter, a bass coil (with a broad conductor cross-section), and part correction (with thin wire cross-section). Precision, dynamic, subtle tonal gradations, incredible detail, and liveliness distinguish coils with air core from all others. They are, therefore, the foundation for practical and harmonic musical experience in high-quality speakers. Modern self-supporting design, low inductance tolerance of +/-3%, and power handling depending on the wire used to make it the most versatile coil on the market.
The current it holds has little effect on its inductance. The inductance of ferromagnetic core coils, on the other hand, begins to increase at low field strengths until decreasing to zero as saturation reaches. In some cases, such as switching converters, non-linearity in the magnetization curve can be accepted. However, in circuits such as audio cross over networks in hi-fi speaker systems, distortion must be avoided. Therefore, an air-core coil is needed — this also why most radio transmitters use air coils to stop the creation of harmonics.
Also, 'Iron losses,' which damage ferromagnetic cores, are absent in air coils. As the frequency has increased, this advantage becomes progressively more important. One obtains a better Q-factor, greater efficiency, more excellent power handling, and less distortion.