Re: Single Shot
From: Julian Green[SMTP:julian-at-kbss.bt.co.uk]
Sent: Wednesday, August 06, 1997 12:30 PM
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).
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
I assume that the coupling between scope probe and TC is capacitive.