The 4.5T Air Core Copper Inductor Coil is a precision-wound, wire-hollow (coreless) RF inductor designed for high-frequency resonant circuits, RF tuning, signal filtering, and wireless communications. Constructed using 0.7mm high-purity enameled copper wire with an inner diameter of 3.5mm, this 4.5-turn air-core inductor delivers an ultra-high Quality factor (Q-factor), zero magnetic core saturation, extremely low parasitic capacitance, and stable inductance across wide temperature and frequency ranges. Supplied in a bulk 1000-piece pack, it is ideal for high-volume RF electronics manufacturing, automated assembly lines, FM/VHF transceiver production, and RF prototyping.

Specifications

• Product Type: Wire-Hollow Air Core Inductor / RF Choke Coil
• Number of Turns: 4.5 Turns (4.5T)
• Wire Gauge / Diameter (G): 0.7mm Enameled Copper Wire
• Inner Coil Diameter (D): 3.5mm (±0.2mm)
• Inductance Range: Approx. 30nH to 50nH (Depending on turn pitch and lead length)
• Core Type: Air Core (Hollow / Non-Magnetic)
• Conductor Material: 99.9% High-Purity Polyurethane/Polyester Enameled Copper Wire
• Lead Finish: Pre-stripped and pre-tinned for direct, easy through-hole soldering
• Operating Frequency Range: VHF / UHF (Typically 40 MHz to 450+ MHz)
• DC Resistance (DCR): Extremely Low (< 0>
• Current Handling Capability: High (≥ 3.0A to 5.0A continuous depending on ambient cooling)
• Operating Temperature Range: -40°C to +125°C
• Pack Quantity: 1000 Pieces (Full Bulk Pack)

Features

• Zero Core Saturation: Air core geometry completely prevents magnetic saturation, hysteresis loss, and harmonic generation under high RF power levels.
• High Quality Factor (Q): 0.7mm thick solid copper wire minimizes high-frequency skin-effect losses, providing high selectivity in tuned LC filters.
• Pre-Tinned Solder Leads: Enamel is pre-stripped and leads are pre-tinned for immediate wave soldering or manual PCB assembly.
• Mechanically Stable Structure: Heavy 0.7mm copper wire offers excellent mechanical rigidity, preventing vibration-induced inductance shift.
• Ultra-Low Parasitic Capacitance: Open-pitch turn spacing ensures a high self-resonant frequency (SRF) deep into the UHF spectrum.

Common Applications

• FM & VHF Transmitters / Receivers: LC tank tuning, intermediate frequency (IF) filters, and local oscillators.
• RF Power Amplifiers: Impedance matching networks and DC supply RF chokes for VHF/UHF transceivers.
• Wireless Communication Modules: High-frequency filtering and antenna matching in 315MHz, 433MHz, and 868MHz wireless transceivers.
• Low-Pass & Band-Pass Filters: Harmonic suppression and signal filtering in RF front-end modules.
• RFID & Remote Control Devices: Resonant inductive coupling circuits in keyless entry and telemetry transmitters.

Usage Tips

• Manual Inductance Adjustment: Fine-tune the circuit resonant frequency by gently compressing the turns together to raise inductance, or expanding the pitch to lower inductance.
• Soldering Precaution: Solder directly to the pre-tinned leads without excessive heat dwell time to prevent enamel degradation near the active coil winding.
• Clearance & Shielding: Maintain adequate physical clearance from large ground planes and metal shielding cans to avoid parasitic capacitance and eddy-current Q-degradation.
• Mechanical Fixing: In high-vibration or mobile equipment, secure the inductor body to the PCB surface with a drop of neutral-cure non-conductive electronic adhesive.