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Re: Mini Tesla

Tesla List wrote:
> 
> Original Poster: NickandSim-at-aol-dot-com
> 
> Bert,
>        I am very grateful for your advice.  The cap value was a typo in my
> mail.  It is actually 0.01uF.  I am also switching to a 6kv 15ma transformer
> and a 0.005uF cap some time soon.  Also please remember that frequency
was in
> KILOHETRTZ not MEGAHERTZ and is therefore a VERY long way from being a
> microwave.
> What are multiple spark gaps? are they in series, parrallel, how do you
> calculate the gap etc.
>                                                  Nick Field
> 

Nick,

A 0.01 uF cap may be on the large side for your 6 kV 15 mA transformer -
but the planned 0.005 uF cap should work very well. Multiple spark gaps
are just that - the main spark gap is designed so that there is more
than one sparkgap electrically connected in series. For example, one
popular low-medium power design uses a number of identical pieces of
hard copper tubing that are spaced 0.010 - 0.030" apart (side-by-side).
The total breakdown voltage of the combined gap can be adjusted by
either adjusting the individual gap distances or (much simpler)
selecting the specific piece of pipe to necessay to obtain the desired
total gap spacing. 

Obviously, higher voltage transformers can support a larger number of
gaps. This type of gap is called a "static gap", and may employ forced
air cooling to assist in removing heat and ions inside the gaps.
Individual gap spacing will govern the per-gap breakdown voltage, and
the gaps are typically spaced to break down at 1000 - 2000 volts/gap.
Total gap voltage is approximately additive - a group of six
series-connected gaps, each having an average breakdown voltage of about
1000 volts, will break down at about 6000 volts.

For construction details on various types of static gaps see the Tesla
Builders List Archives at: 

http://www.velocity-dot-net/~djb/files.shtml 

and check out Sparkgap.zip. Additional information can be found by
searching the archives at CVhip Atkinson's Tesla Coil Builders List:

http://www.pupman-dot-com/

Safe coilin' to you!

-- Bert --