FT140-43 NiZn Ferrite Toroid Core 36x23x12.7mm | 850µ Mix 43

FT140-43 Nickel-Zinc Ferrite Toroid Core – High Permeability RF & EMI Filtering

The FT140-43 Nickel-Zinc Ferrite Toroid Core is a precision-engineered, ring-shaped magnetic core designed for RF chokes, EMI suppression filters, broadband transformers, and power inductors. With an outer diameter of 36mm, inner diameter of 23mm, and height of 12.7mm, this toroid delivers high permeability rated at 850 (±20%) — ideal for amateur radio (ham radio), telecommunications, and electronics hobbyist applications.

Made in Mainland China.

Key Features

• Material: Mix 43 Nickel-Zinc (NiZn) Ferrite
• Dimensions: OD 36mm × ID 23mm × H 12.7mm (equivalent to FT140 size)
• Initial Permeability (µi): 850 ±20%
• Frequency Range: Optimized for 1 MHz – 300 MHz applications
• Core Shape: Toroidal (ring) — self-shielding, low leakage flux
• Color: Typically grey/nickel finish (characteristic of Mix 43 material)
• Application: RF chokes, baluns, EMI/RFI filters, broadband transformers, common-mode chokes
• Non-electrified: Passive component, contains no high-concern chemicals

What Is Mix 43 Ferrite?

Mix 43 is a Nickel-Zinc ferrite compound widely recognised in the RF engineering community for its excellent broadband suppression characteristics across HF to VHF frequencies. It is especially effective for winding common-mode chokes and 1:1 or 4:1 baluns used in antenna feed lines and transceiver circuits. Its high permeability makes it efficient at suppressing unwanted common-mode currents with fewer winding turns.

Common Applications

• Amateur (Ham) Radio — baluns & antenna chokes
• EMI / RFI noise suppression in power supplies
• Broadband RF transformers
• Common-mode chokes for USB, audio, and data lines
• Switch-mode power supply (SMPS) inductors
• Educational & hobbyist electronics projects

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External Reference

For background on electromagnetic compatibility (EMC) standards and ferrite component performance guidelines, visit the NIST Electromagnetic Fields Group.

Learn more: Ferrite core

Frequently Asked Questions

Q: What frequency range is the FT140-43 nickel-zinc ferrite toroid core best suited for?

A: The FT140-43 Mix 43 NiZn ferrite toroid is optimised for use across approximately 1 MHz to 300 MHz. It is particularly popular for HF and VHF amateur radio baluns, broadband RF transformers, and common-mode choke applications in this frequency band.

Q: What does the permeability rating of 850 (±20%) mean for this ferrite core?

A: Permeability (µi) indicates how effectively a material concentrates magnetic flux compared to air. A rating of 850 ±20% means the FT140-43 ferrite toroid has very high magnetic permeability, allowing you to achieve the required inductance with fewer winding turns — saving wire and reducing winding resistance in your RF choke or transformer design.

Q: What is the difference between Mix 43 and other ferrite mixes like Mix 31 or Mix 61?

A: Mix 43 (µi ≈ 850) offers the broadest HF suppression bandwidth and is excellent for common-mode chokes and baluns across 1–300 MHz. Mix 31 (µi ≈ 1500) is better below 10 MHz (MF/LF), while Mix 61 (µi ≈ 125) excels at VHF frequencies above 200 MHz with lower loss. Mix 43 strikes a strong balance for general HF ham radio and EMI suppression use.

Q: Can I use this toroid core in a switch-mode power supply (SMPS)?

A: Yes. The FT140-43 ferrite toroid is suitable for use as a common-mode choke or output filter inductor in SMPS designs operating in the HF range. Ensure your operating frequency and flux density requirements fall within the core's rated parameters for best performance.