[TowerTalk] Trifilar Winding Question

[Andy]

> I did a study of this about 10 years ago.  Garden variety ribbon
> cable has a characteristic impedance of 150 ohms.

The characteristic impedance is dependent on how the cable is used ... which
wires are signal, and which ground.  For example, G-S-S-G is different than
a G-S-G-S-G configuration.

Not having done a thorough search ... I recall seeing ~110-120 ohms as a
typical impedance for flat ribbon some years back, for certain uses.  (I
think this was old SCSI, not sure anymore.)

OTOH, and again not being very well versed on such things, I'm not sure how
the characteristic impedance of the wires matters in this case when winding
transformers.  Plus the impedance would surely be reduced by the proximity
with lots of other metal around it (other coils, the core, etc.).

Andy