Re: chokes

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Peter,

As far as I know, when the gap first shorts, it discharges the capacitance
between the gap's electrodes.  Although this stored capacitive energy is
not that great, the very very short time that energy is dissipated creates
giant, very high frequency, currents (very little inductance or resistance
to slow the capacitive discharge).  These are what show up as white dots on
the neighbor's TV and the neighbors TVs a few blocks down =:O

Adding ferrite chokes tends to slow the discharge and decrease the noise
significantly.  Note the big ferrite cores on the stationary and rotating
electrodes of my big rotary gap:

http://hot-streamer-dot-com/TeslaCoils/MyCoils/BigCoil/Rgap.jpg

These parasitics being discharged are really hard to accurately model, but
when one guesses at them and adds them to simulations, the effects are very
clear and similar to the actual readings.

I like to connect the NST across the gap since the gap acts like a short
that tends to stop the RF from going further to the NST.  The primary cap
sees the full RF voltage across it and that voltage is sent to the NST if
the NST is connected across the primary cap.

Cheers,

	Terry



At 03:36 PM 10/4/2001 -0700, you wrote:
>Terry,
>      is this "spike at the beginning..." the illegible stuff in the trace
>you made of a simulation comparing connecting the NST across the primary
>cap verses across the spark gap that is in one of your web pages.
>
>Does this argue that there is a reason to use an RC filter even if you do
>connect your NST to the spark gap rather than to the capacitor.
>
>thanks,
>Peter Lawrence.
>
>
>>Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>>
>>Hi Ed,
>>
>>At 07:54 AM 10/4/2001 -0700, you wrote:
>>>> Hi Greg,
><<<... stuff deleted ...>>>
>>
>>There is also a nasty high voltage spike at the beginning of gap condution
>>that is rich in up to GHz harmonics, but will will just try crawling first 
>;-))
>>
>>Cheers,
>>
>>	Terry
>