Camcorder DC power cord core filter - woo or science?

[catbasket]

My JVC camcorder was supplied with a Core Filter - a 3cm long plastic gizmo with metal inserts - around which you loop the AC power adapter's DC cord to "reduce interference". The grand total of info about the core filter in the manual is -

Attach the core filter to the AC adapter's DC cord. The core filter reduces interference. [plus diagrams showing how to fit the core filter to the DC cord]

I've used the AC adapter to charge the battery pack and also power the camera while transferring files to PC, without connecting the core filter to the DC cord, with no problems whatsoever.

Is the core filter woo or real science? If science - what does it do, how does it work and why is it a seperate gizmo clipped onto the DC cord rather than part of the power adapter?

[Freethinker]

It's probably a ferrite device that will filter out high frequency noise on the line that can be created by electrically noisy devices like fluorescent lighting.

[technoextreme]

My JVC camcorder was supplied with a Core Filter - a 3cm long plastic gizmo with metal inserts - around which you loop the AC power adapter's DC cord to "reduce interference". The grand total of info about the core filter in the manual is -



I've used the AC adapter to charge the battery pack and also power the camera while transferring files to PC, without connecting the core filter to the DC cord, with no problems whatsoever.

Is the core filter woo or real science? If science - what does it do, how does it work and why is it a seperate gizmo clipped onto the DC cord rather than part of the power adapter?
It's not woo. It's just something you don't usually deal with on a daily basis. Check your computer. 1000% certainty that your computer has the same device. It's the big giant bump in the cable.

[marting]

My JVC camcorder was supplied with a Core Filter - a 3cm long plastic gizmo with metal inserts - around which you loop the AC power adapter's DC cord to "reduce interference".

I've used the AC adapter to charge the battery pack and also power the camera while transferring files to PC, without connecting the core filter to the DC cord, with no problems whatsoever.

Is the core filter woo or real science? If science - what does it do, how does it work and why is it a seperate gizmo clipped onto the DC cord rather than part of the power adapter?

Manufacturers add these devices to reduce high freq common mode RF emissions for regulatory reasons. A device that otherwise radiates slightly more RF than is allowed will often meet specs with these. It has no effect on the operation since it doesn't alter differential signals within the wire cable.