Ferrite toroidal core 3.5 mm, round, black — EFB Elektronik 71501.1

EFB Elektronik ferrite toroidal core with a 3.5 mm inner diameter, round cross-section and black finish is designed to reduce electromagnetic interference (EMI) and suppress high-frequency noise in cable assemblies and electronic circuits. The compact toroidal shape allows conductors to be wound or passed through the core to increase impedance at interfering frequencies, improving signal integrity and reducing emitted or received noise in power supplies, data lines and signal cables.

Advantages

The toroidal core provides a concentrated magnetic path that increases impedance for high-frequency currents while preserving low-frequency performance. Its small 3.5 mm inner diameter and round profile make it suitable for both single-turn clamp-on use and for winding multiple turns of thin conductors. The black ferrite material is stable across a wide frequency range and offers a balance between suppression effectiveness and compact size, facilitating easy installation in tight spaces or retrofit repairs.

Suitable for

Key specifications

How to use

Pass the conductor or cable through the centre of the toroidal core one or more times, or wind the conductor around the core to increase effective impedance against high-frequency noise. For clamp-on style installations, slide the cable through the inner diameter and position the core near the source of interference or close to connectors and entry points. Ensure the cable insulation is intact and avoid excessive mechanical stress on the core during assembly.

Recommendations

For best results, test the number of turns and core placement while monitoring the circuit for noise reduction. Use multiple turns or several cores in series for higher attenuation, and combine with proper grounding and cable routing to achieve optimal EMI suppression.