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Re: Help please
Hi Neil!
Tesla List wrote:
>
> Original Poster: Neil Walker <ndwalker-at-tpgi-dot-com.au>
>
> Hi from the 'tipodes,
> Recent posts suggest that P.C.B.s won't float on
> water.Is this a reasonably conclusive test ?
Specific Gravity is about 1.5X that of water. Also, the sweet-solvent
odor (benzene-like) is also quite noticeable in PCB-based transformer
oils. Mineral oil lacks the strong odor, and will float in water.
> A 1924 text which I'm reading speaks highly of zinc
> for multiple stationary s-gaps. Could anyone comment ( or direct me to
> previous posts ) ?
Zinc was used in lower-power static, and for stationary electrodes in
rotary gaps earlier this century. Today, the best overall performance
(long life, good quenching, reasonable voltage drop and series
resistance) is still obtained with Tungsten, Tungsten-Copper (Elkanite),
or copper. Most multiple-gap quenched sparkgaps were constructed from
copper, even back then.
Zinc was sometimes used in part because of work done by P. Drude which
showed that sparks between zinc balls gave the lowest damping (i.e.,
lowest effective spark resistance) for single-spark discharges. Other
experiments done by Professor A. Slaby showed lowest spark resistance by
using cadmium, tin, and silver, while steel balls were 30% higher spark
resistance than most other metals. However, I don't know if these early
experimenters had access to tungsten electrodes...
Out of curiosity, which 1924 text are you reading?
> I've been lurking in the wings for a while now, and
> enjoying every minute of it .Many thanks for a terrific exchange of
> information.
> Regards
> Neil Walker
The best in the world... :^)
-- Bert --