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FrozenGate by Avery

Help wiring a flyback transformer.

For this driver, a breadboard ought to work fine. Personally, I'd just get protoboard; you'll need it for other things too if you enjoy HV.

Yes, small resistors will work fine for everything.

For the capacitor, (the filtering one) I'd keep it at or above 16 volts.

And, 5 - 25 turns of wire around the ferrite, yes. 24-22 gauge wire works perfectly for this.

More turns equals less current draw, at the expense of less arc output.

Less turns equals MORE current draw, while giving longer and hotter arcs. Of course, with the additional current draw your mosfet will heat up more... a lot more. You'll need a pretty decent sized heatsink to run it for any amount of time!
 





That's about a half mm diameter, right? I think the wire from a small transformer that was also on the board will do just fine.

I think I'll start with 20 turns to get the feel of it - if I manage to remove the plastic.

I'm also curious about how the circuit works. I guess the resonance from the feedback coil has been replaced by a tunable oscillator and that's what the pot is for, right?

Thanks!
 
Yep! The 555 timer just turns the mosfet on and off at a time based off of RC constants through the series of resistors and the capacitors for the 555 timer.

It uses Flyback topology (that's how they work inside the TV!) which basically involves pulsing the primary, as opposed to giving it "true" AC.
 
@Le Quack: One last question, ATX PSUs have a -12V cable but from what I've read the -12V takes very little current. Do I need 2 PSUs in series to get 24V or 12V will do? If 12V does the job can I skip the 7812 voltage regulator?

@Sigurthr: Indeed! Those are huge arcs, do you control the thickness by limiting current?
 
If you use just 12 volts straight off the bat, no regulator is needed. Once you get over around 15 volts, I would recommend adding it.

And no, you cannot put them in series...more or less they'll fight eachother for regulation and end up oscillating and bad stuff happens.

Those arcs in the video are from a ZVS driver, a self resonant Royer oscillator that uses zero voltage switching to keep the transistors nice and cool. Not a half bridge, but a push-pull driver Sig!
 
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yes you can if you are using the 12V rail of the computer PSU. Bear in mind that a lower input voltage = smaller arcs on the output.

edit: le quack beat me ;)
 
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Hehe, sorry! Well, you'd know Jared! I hate trying to reverse engineer point to point in to a schematic view so I can determine topology XD. I'll fix the vid.
 
Pft, it's alright Sig. :p I would've probably said the same thing too if I didn't know what it was. xD
 
Hehe. Aye, all I did was rebuild it because it fell apart in transit and take care of the primary winding, haha. I cannot claim credit for it's design XD.

The HVDC one you built me I do understand the circuit design/theory of though. And since my endeavors with SSTCs I now understand the power amp (mosfet half bridge) side of the Plasma Speaker, but not the audio modulation side of it. I assume it is frequency modulation from the audio fed to the enable pin of a gate drive chip and the arc performs slope detection turning it in to amplitude modulation for our ears, but that is just my guess.
 
It IS frequency modulation, but not frequency modulation...

It is basically a Class D amplifier, without the low pass filter on the output. (so, yes, it technically would work as an amplifier too if you hooked up a low pass filter + speaker)
 
Right, instead of it going to a low pass filter and a speaker it goes to the primary of a LOPT and you get modulated HV out. Okay, that's what I thought.
 
@Le Quack: Can I use a KSP42 instead of the MPSA42? The store only had that one and the datasheet seems very similar to my untrained eyes.
 
I think I have everything now, except for the breadboard (had to order that online). Will start construction as soon as this damn flu goes away :)
 
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