On 2020-10-17 06:01, mike tucknott via Tesla wrote:
Hi All
With a bipola coil would having 2 movable tap point work for changing
the coupling ?
Say the coil need 5 turns to be in tune, you could built the primary
with 10 turns and you could move the inner and outer taps points in or
out but still keeping the 5 turns needed to keep the coil in tune, the
inner and outer turns passed the tap point would be electrialy dead so
to speak.
Thoughts on this one guys.
Cheers Mike T
I think that changing the coupling by changing the diameter of the
primary is the way to go. What you propose would accomplish that
effectively. However I think the unused are not dead. They are still
coupled and generating potential at the open ends. When you are tapped
at the outermost turns for minimum coupling there may be some unexpected
"coupling" in the form of D'Arsenval currents. Of course if you could
remove the excess turns it would work fine:-)
Perhaps a solenoidal spring wound from beryllium copper or phosphor
bronze. Wound tightly would be small diameter with most turns. untwist
for large diameter and least turns. Someone else can figure the change
in inductance due to change in diameter vs due to change in number of
turns:-)
In any case your idea of changing the diameter, that is the ticket.
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxxxxxx
https://www.pupman.com/mailman/listinfo/tesla