RF Chokes/Ferrite Beads, do they have a place in your system?

Hello and thanks for responding!

I have a large collection of chokes/beads and was curious if they have a place in your system and what benefit, if any, they may have. I have tried them only on power cords where "maybe" there was an audible improvement. Are there other areas of a system where they may be desirable to install?


Showing 1 response by vk_onfilter

Ferrite beads/clamps roughly act as a transformer where the primary is the cable or wire in the clamp and the secondary is shorted.  The end result is that high-frequency current is converted into heat.  Since the high-frequency (EMI) currents are fairly low unlike 50/60Hz mains currents, the amount of this heat is minuscule.  Absolute majority of ferrite materials are targeting high-frequency spectrum (tens of MHz and up).  They don't address low-frequency (tens of kHz to few MHz) conducted noise that is prevalent on AC power.   The main purpose of ferrite beads/clamps is to reduce radiated emission (30MHz and up) for EMC test - any cable is an antenna and these ferrites introduce losses making what would be a good antenna a bad antenna.  One should expect perhaps 10dB attenuation which may be just enough to pass CE/FCC radiated emission test.  If you are looking to reduce conducted noise on AC mains, ferrites would be of very little help - you would need to have an AC EMI filter for that.