Re: Variable Cap In Secondary?

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

Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-uswest-dot-net>" <bert.hickman-at-aquila-dot-net>

Jake,

The author was apparently referring to the practice of using various
diameter toploads (for gross tuning) and then adjusting the elevation above
the coil for fine tuning. This will indeed allow a degree of tuning on the
secondary side. However, MOST Tesla coils are fine tuned by adjusting the
primary inductance or capacitance. There have been some experiments
performed by chaining a string of high voltage capacitors through the
center of the secondary (I believe Greg Leyh did this at one stage in the
development of Electrum). A vacuum variable cap would not have sufficient
holdoff voltage to do the trick for other than a very small coil. 

Best regards,

-- Bert --
-- 
Bert Hickman
Stoneridge Engineering
Email:    bert.hickman-at-aquila-dot-net
Web Site: http://www.teslamania-dot-com

Tesla list wrote:
> 
> Original poster: "Jake Draper by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <cybermecium2-at-home-dot-com>
> 
> I was looking around on the net for information about Tesla Coils and I
> stumbled accross an About-dot-com Physics Dictionary definition stating that
it is
> a device to create high voltage at high frequency. I already knew that,
but it
> says something about a variable capacitor with the secondary to tune it with
> the primary. Has anybody ever seen or heard of anything like this? The URL is
> <http://physics.about-dot-com/science/physics/library/dict/bldefteslacoil.htm>h
> ttp://physics.about-dot-com/science/physics/library/dict/bldefteslacoil.htm