Hi Chris,
Thanks for these very interesting results. In my 555 setup, I neverthought of using a narrow pulse like that. My pulse was verywide... wider than the entire 60Hz positive AC half cycle. Mywide pulse must be affecting when the next pulse occurs, sothe next pulse is skipped thus giving only 30 PPS max.
I remember when I added a Schmitt trigger onto my originalTTL logic circuit, it changed the pulse in some way whichI don't quite remember but I think it improved the operation.
I agree that the pulse should have some lead time as inyour breadboard circuit. If there is no lead time or not enough,then the Tesla coil doesn't quite know whether to run or not,and it misfires and gives the weak branched results. Oncethe tube starts oscillating, the pulse cannot stop it. The pulsecan only prevent it. I experimented with a different idea thatI called "duty cycle control" where I limited the duration ofthe oscillation during each AC half cycle, but this gave nobenefit because most of the energy is at the peak. This methodrequired a lot of negative voltage to shut the coil off while itwas running, as you can imagine.
It should be helpful to compare the schematic for the breadboard circuit vs. the EVR circuit to see what'sgoing on with the triggering that makes it impossible toobtain more lead time. I vaguely remember seeing thiseffect in my 555 circuit so I readjusted things to createsome lead time. I don't remember how I did it, but itresulted in the extra wide pulse.
John
-----Original Message-----
From: Chris Reeland <chrisreeland@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Sun, Oct 27, 2019 10:02 am
Subject: Re: [TCML] Eastern Voltage Research VTTC Staccato Controller - puzzled on "burst" output
Hi John,
Here is a couple of pictures of the scope traces.
https://photos.app.goo.gl/t11KzCPW1gapTvbY7
Picture #1 and #2 are of the "breadboard" interrupter at minimum and then
maximum PW. I notice the extra lead time before the rise. Previously in the
past this is what I had also. Wanted to reverify this and confirmed.
Picture #3 and #4 are of the EVR again at minimum and maximum PW.
Note the very little lead or right on the rise.
Another note here, when PW is past the peak, PRF can only get up to 30Hz.
So bypass switch has some usefulness when maximum PW. Of course, if you
reduce PW to the peak, then instantly back up to 60Hz. Did not catch this
before, when testing on scope.
Pictures #5 and #6 are just adjusting the EVR so the PW does not go past
the peak.
Going to now do some more running coil tests...
Chris Reeland
Ladd Illinois USA
Sent from my LG V20
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