Air core coil
Core structure and composition
Wire material: usually copper or aluminum wire (low resistance, high conductivity), the surface may be silver-plated or coated with insulating paint.
Winding method: spiral winding (single or multi-layer), the shape can be cylindrical, flat (PCB coil) or ring.
Coreless design: the coil is filled with air or non-magnetic support material (such as plastic frame) to avoid hysteresis loss and saturation effect caused by the iron core.
Key parameters and performance
Inductance: lower (compared to iron core coils), but can be increased by increasing the number of turns or coil area.
Quality factor (Q value): Q value is higher at high frequencies (no iron core eddy current loss), suitable for radio frequency (RF) applications.
Distributed capacitance: Coil turn-to-turn capacitance may affect high-frequency performance, and winding spacing needs to be optimized.
Resistance: Determined by wire material and length, DC resistance (DCR) affects energy consumption.
Advantages and disadvantages
Advantages:
Excellent high-frequency performance: no iron core loss, suitable for RF and microwave circuits.
No magnetic saturation: stable inductance under high current, suitable for pulse and high dynamic scenarios.
Lightweight: simple structure, light weight, low cost.
Disadvantages:
Low inductance: the inductance value is much smaller than that of iron core coils at the same volume.
Weak magnetic field strength: requires larger current or more turns to generate the same magnetic field.
Typical application scenarios
High frequency circuits:
RF choke, LC resonant circuit, antenna matching network.
Sensors and detection:
Metal detectors, contactless current sensors (Rogowski coils).
Medical equipment:
Gradient coils for MRI systems (to avoid magnetic interference).
Power electronics:
High frequency transformers, wireless charging coils (to avoid heating of ferrite).
Research fields:
Helmholtz coils (to generate uniform magnetic fields).
FAQ
A: We are a factory.
A: We have 20 years of spring manufacturing experience and can produce many types of springs. Sold at a very cheap price.
A: Generally 5-10 days if the goods are in stock. 7-15 days if the goods are not in stock, by quantity.
