MiniBrute DRSSTC
From Simreal
I've finally put my foot into the high-voltage pool, building Daniel McCauley's miniBrute tesla coil off of his book and circuit boards from this site. Yeah, a "kit" is cheating, but I figured it would be the best way to get some high-voltage analog experience before I launch off and do my own thing... which should be exciting! Of course, McCauley has some new stuff on his site, too (a new power driver, some musical control boxes), but I prefer not to be too derivative so I'll definitely be branching off (with full credit to McCauley, Steve Ward, Jimmy Hynes, and other pioneers in this field, but I really don't want to get into the politics of the HV/Tesla world). The place to be (where ALL the cool sparkheads hang out) is 4HV.
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So far I'm getting about two-foot lightning off of this, and then it blows the fuse in my variac, so I need to work on that. I'm thinking I'm getting some bad noise up the power line (I saw an arc in the variac's voltmeter, which I figure is a bad sign), so power filters are in my future.
Even with a TINY TINY powerup on the coil, my antennae, a few feet away, shows hundreds of volts on my scope. It's quite the transmitter at about 176kHz (I wonder what that channel is?)
In tuning it, I'm doing an FFT off of this antennae, for lack of a better idea. First, of course, I did LC measurements with my signal generator (which has a blind spot around 200kHz, right where my resonance is, lucky me), and those pointed me at the 190kHz range. And now the FFT.
In the FFT (scope shots someday later maybe) I see a nice peak at 175kHz, which I can move up and down by changing my primary tap. Then I see a gratifying smaller peak at 194kHz, which must be the secondary, since it is fixed.
When I power the coil up, that secondary peak drops into a notch as the primary peak goes through the roof. Fascinating!
If I tune my primary down or up from the 170+/- area, my sparks get all kinds of wimpy, so I expect the lightning off the toroid is adding capacitance (as expected) and tuning the double bump into a single bump?
Except I don't see the peaks merge, I just see the 194kHz one drop off into a NOTCH. So I don't know. I'm still learning -- gotta get my analog guy in here to improve my education.
Fascinating stuff, though. I'm going to have to write a book... tesla coils are a great testbed for analog education.
A video test of the tesla (next to the FlamePillar) is here.
