ken scharf ) writes:
Clayton wrote:
Hi,
I have a coil that is wound on a 1.125 inch diameter form and 3 inches
long space wound with 25 turns of 11 gauge aluminum wire...
I am trying to duplicate this coil only instead of using 11 gauge wire
I am using 12 gauge aluminum wire.
I was wondering if somebody could help me out and make sure my math is
right since I am unsure of how to go about making sure I match the
inductance.

I had this figured out once but mistakenly had the wrong wire
gauges...

Any help is greatly appreciated
Thank You

So long as the new coil is wound at the same pitch as the old coil
the inductance will be the same. Since you want to use a higher
gauge wire (thiner) this will be easy to do. The pitch, is of course,
the number of turns per inch. So if the old coil was close wound, the
new coil will be slightly space wound (air spacing between each turn of
wire).

It's worth adding that the size of the wire is often specified because
either that's what fits on the coil form (ie if you need X number
of turns, a bigger guage won't allow that number of turns in the
space) or because there is reason for using heavier guage (such
as because it's carrying higher current, or you want it self-supporting).

Coils don't exist by themselves. To serve a purpose, they are associated
with capacitance, and that capacitance will allow for adjustment, and
may even require adjustment even for a "perfect coil" since there
will stray capacitance from the circuitry that never shows up in
a schematic, and stray capacitance from the coil itself.

Michael