The Ferrite Ring Combo Pack is a convenient solution for troubleshooting RFI/EMI from unknown frequencies or multiple frequencies that require multiple suppression mixes. Included in this combo pack are ten 1.4″ OD/.9″ ID ring toroids as follows:

Mix 77 effective from .1-50 MHz including AM Broadcast band – quantity: 2

Mix 43 effective from 25-250 MHz for general purpose – quantity: 2

Mix 61 effective from 200-2000 MHz for cell phone, WIFI, HDTV, Cable TV interference – quantity: 2

The ring toroids are useful for AC/DC common mode choking with multiple turns as shown below

AC Cable on F-240 Toroid – 7 turns

DC Cable on F240 – 4 turns

The ring toroids can also be used on coax or signal lines as shown below:

RG58 12 turns on FT240

Ethernet Cable on F-240 Toroid – 7 turns

For RFI/EMI wrap as many turns as possible for higher choking (under 30 MHz). For over 30 MHz, 1-3 turns is usually sufficient due the to capacitive effect of multiple turns reducing choking effect.

The rings are also useful for making impedance transformers like 4;1, 9:1, etc.