heaudio123 They don’t have to be separated, but they often are because it is easier to wire, for isolation, and to reduce capacitance between coils. Common mode air choke has to be wired with a pair of wires (interleaved) because of leakage flux. Such coil is called bifilar coil and is used to wind non-inductive resistors. Look at the first picture on the top of this link: https://en.wikipedia.org/wiki/Bifilar_coil
It doesn’t matter that right side is shorted - you can cut it and connect speaker there. It will still work exactly the same, since opposing currents are identical. Wikipedia description "Bifilar coils impose an inductance in the common mode, but impose no inductance in the differential mode" is basically definition of common mode choke.
It doesn’t matter that right side is shorted - you can cut it and connect speaker there. It will still work exactly the same, since opposing currents are identical. Wikipedia description "Bifilar coils impose an inductance in the common mode, but impose no inductance in the differential mode" is basically definition of common mode choke.