Ferrite cores, just what do they do?

[admin_exported]

My new tv came with 2 ferrite cores, whch it says should be fitted to the ethernet cable at each end to comply with some EN or other. I also have one which was factory fitted to the mains cable on my dvd player. What exactly are they for, and are they needed?

So far according to little Ell (3) theya have been space rockets, noculars, submarines and (once he figured out how to open them) 'grabbers'.

 

[True Blue]

They're a ceramic-like magnetic material that is mostly used to to absorb EMI.

Apparently,they strip away musical information when used on analogue interconnects and aren't recommend for that application.

They're probably best used on power cords to reduce noise.

The ferrite ring increases the cable impedance at high frequencies but should preferably not affect the impedance in the audible range, or at the AC frequency. Obviously it is easier to achieve this at 60 Hz than over a great bandwidth.

 

[Anonymous]

My interconnects with two ferrite cores sound great (and bright as it happens). No idea what they do.

 

[Anonymous]

Thanks True Blue. You had me up to the last paragrah. I think I'll leave them off for now. I don't want to spoil Ell's fun. They kept him out of the box at least till I could store it away.

 

[True Blue]

Did say "apparently"

 

[aliEnRIK]

There are various 'grades' of ferrites, they all remove (Some) RFI in the signal

NOT to be used with video signals, as its the higher freqencies that are reduced

 

[RobinKidderminster]

Forgotten my amp had some. On or off then ? Advice would be appreciated.

Cheers

 

[idc]

You will find them on many cables connecting to and from PCs as they reduce background noise.

 

[Anonymous]

I take it the cylindrical bit of plastic already fitted to some mains cable near the product are ferrite cores? My That HDMI cable must have them. I never really knew what they were. The two which came with the tv are user attached. If they are any good how come companies like Chord don't fit them to their cables? or do they feel their shielding is enough.