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RE: Single Shot
From: Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Thursday, August 07, 1997 12:55 AM
To: tesla-at-pupman-dot-com
Subject: Re: Single Shot
Hi Julian,
Thankyou, thankyou for going out and *trying* these tests.
I am over the moon that somebody has *done* it rather than sit there
and speculate. I am extremely indebted to you. You have made my day :)
> From: Julian Green[SMTP:julian-at-kbss.bt.co.uk]
> Sent: Wednesday, August 06, 1997 12:30 PM
> To: tesla-at-pupman-dot-com
> Subject: Re: Single Shot
>
> Thankyou Malcolm for your post I have repeated the scope tests
> you describe and have observed the same. The mark space ratio of a
> running coil clearly shows that the secondary is at complete rest before
> the next bang, thus disproving the idea that the energy in a ringing secondary
> is from multiple bangs. Taking a closer look of the waveform when the coil
> is allowed to produce streamers shows that all the energy in the secondary is
> transfered into the streamer on the first half cycle of RF (on my coil).
I would expect something like that at higher power levels :)
> Coil running - no streamers.
>
> Low scope time base looks like this:
>
> | | | | | |
> -----+-----+-----+-----+-----+-----+----
> | | | | | |
>
> Each spike being a firing of the gap.
>
> Faster time base using +trigger and you get this, only
> many more cylcles and shows nice decay.
>
> /\
> / \ /\
> / \ / \ /\
> --- \ / \ / \-------
> \ / \/
> \/
>
> When grounded rod used to generate streamers output looks like:
>
> /|
> / |
> / |
> / |
> ----- ------------------
>
>
> You dont need a storage scope to get these, just a cheap 20MHz scope
> with HF trigger. Connect short length of wire to scope probe and
> set up away from the coil. Good traces are visable on the 20v/div
> scale. For your single shot tests adjust input power to obtain
> intermittent firing of the spark gap.
>
> Peek voltage or trace amplitude is at a maximum when no streamers are
> being produced.
>
> I assume that the coupling between scope probe and TC is capacitive.
It is.
Many Regards,
Malcolm