More primary AC resistance measurements

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-hp-dot-com>

A couple weeks ago I published the results of a series of AC resistance
measurements of various primary coils.  Many interesting things were noted
and several questions arose as a result of those measurements.

I have just completed a second series of measurements on some new coils.
The new coils were a pair of space and close-wound solid #14 gauge coils, a
two-layer 1/4" copper tubing coil, and a .03" x 1" copper ribbon coil.

The .03" ribbon performed well, but not as well as the 1-layer copper
tubing, perhaps due to a shiny finish on the tubing but a dull brown patina
on the ribbon?

The 2-layer tubing coil performed very poorly, particularly at higher
frequencies.  I'm suspecting that the unused turns at the end or each of
the two coils was a factor here, and another series or test coils and
measurements will be needed to investigate this.

I was surprised that the close-wound #14 coil was marginally better than
the space-wound coil.  I would have expected the proximity effect to have
made the close-wound case worse, but apparently not.

I'd like to again thank D.C. Cox at Resonance Research for the generous
donation of the copper ribbon.  Now all's I have to do is apply a generous
amount of elbow grease and polish it up.

Full data, photos, and graphs may be seen at:
http://www.laushaus-dot-com/tesla/primary_resistance.htm

Regards, Gary Lau
MA, USA