[RFI] Fair Rite #31 Mix Material

[Paul Christensen]

Jim,

One point of confusion is the type of winding employed with a CM choke.  I 
have always wound mine in bifilar fashion.  On some occasions, I have even 
twisted a pair (winding about 6 turns/inch using a hand drill) using 
different colored magnet wire to ensure proper polarity.

However, I keep seeing references to CM chokes being wound with the 
conductors separated symmetrically onto the core.   Please see the core 
illustrations in the link below from muRata:

http://www.murata.com/emc/example/k_3/acpwr_9.html

They seem to imply that the benefit of differential-mode inductance 
cancellation is achieved by splitting the winding as shown,   DM inductance 
cancellation is a very powerful benefit, particularly in audio RFI abatement 
applications.  Does that benefit also apply to a bifilar-wound CM choke 
where the conductors are wound together in parallel around the toroid core? 
Tnx!

Paul, W9AC