Flyback Questions

[etype2]

Electronic M,

I'm very intrigued by your descriptions of the plasma speaker. In theory a perfect sound source with zapping visual effects. How cool is that. :-)

[Electronic M]

Originally Posted by etype2

Electronic M,

I'm very intrigued by your descriptions of the plasma speaker. In theory a perfect sound source with zapping visual effects. How cool is that. :-)

Oh, it was very cool. I brought that thing to my college when I built it, and several of my peers and professors were rather wowed by it. There are some very interesting youtube videos of plasma speakers in action. Mine had very little bass response (typical/expected), and some issues with the arc producing white noise that I never had time to sort out, but it was the most linear tweeter I can recall hearing. Electronic music like Threashold from Steve Miller Band's Book of Dreams album had an almost unreal crispness, clarity and accuracy compared to listening to such tracks on cone or horn tweeters.

Life kinda buried me in work (then distracted me) when I built mine as a proof of concept, but I do plan to eventually get back on refining some into a practical system.

[Alan Sailer]

Electronic M.

In my limited experience with HV diodes they always fail open. This is based on several diode deaths that I facilitated.
Even if you could get the diodes to fail short I doubt it would help. One of the reasons the original design went to internal
rectifiers was to keep from dealing with AC HV issues. Insulation requirement for AC are much more stringent than DC
because AC will propagate through insulation due to parasitic capacitance.

In my AC HV (~20kV) circuit I can run my finger across an insulated wire (40kV DC rated) and get a blue corona discharge
on my fingertip. This doesn't happen with DC.

And corona kills insulation over time.

As far as Tesla coils, I have built a few to try out. And bought a few more. let's say about seven so far. They can be
pretty impressive if the coil is CW and lower frequency. Low frequency means big for an air coil.

Unfortunately they make a poor choice for lighting plasma. Noisy and hazardous. A hit from a tesla coil may not
hurt you. But it sure isn't pleasant.

Cheers.

[zeno]

Using rough numbers, foggy memory & I am NOT an engineer.........

Typical set horz tube draws 200ma at 400V so power is 80 watts.
IIRC a pair is used in home brew ham amps to give a solid 100W.
Waveform at horz out plate is DC with 1KV spikes on top of that
going +. ( DO NOT MEASURE !)
Spikes are very narrow at 15,750. Horz tube is running
very deep class C. The tube is biased off ( -60 to -90 on G-1 )
most of time.
You may want to get an RCA, GE or Sylvania tube manual to help.
Also as many of the same FBT's as you need so you only
engineer them once.

73 Zeno
LFOD !

[Alan Sailer]

zeno,

Your rough number seem in the ballpark to me. I'd be surprised if someone told me horizontal output transformers
are driven at 10 watts or a thousand watts.

Don't worry about measurement stuff I'm perfectly happy with HV as long as it's low power. I've been messing with
HV AC and DC for a number of years and have remained shock free.

miniman82,

All the globe power supplies I have seen (about seven so far) have been some sort of oscillator driving MOSFET(s)
which directly drive a HV step up transformer, usually an un-gapped flyback style. Cascade multiplier put out DC,
not useful for this stuff.

benmann94,

I'll check out Heyboer. I'm guessing they do coils?

The same comment on the Cockcraft-Walton, DC is no good for driving a capacitively coupled plasma globe.

Cheers.