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Class E SSTC thread

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LAN_403

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Thu Jul 13 2006, 02:38PM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

good job BP

Have you put any though into audiomodulation? I seem to remember you trying to use a flyback for some singing plasma, but had problems... I bet that you could get a decent listening volume out of that coil, and beat evr to the first good audiomod coil

The max038 does have a duty cycle input, doesn't it? Perhapse you can just use the detuning effect of the changing duty cycle to get the modulation...

The only things I get to make at work at 555 driven fets to run .25a pulses at 1khz through a coil of wire... I almost got to order some max038's to make a sign wave generator to feed a simple linear amp (pnp transistor) to get a sign wave through the coil, but they decided a square wave would be ok

I am going to try to convince them to let me make my own power supply for it today

Marko

Thu Jul 13 2006, 04:15PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

I was actually wondering when is he going to test his high-Q acrylic litz-wire resonator.
With some topload and proper drive it could make some nice output.
I still don't understand what's he trying with that 2N7000 fet's altough..

*update - class E SSTC dies*

to be continued...

ragnar

Fri Jul 14 2006, 01:20AM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425

Pwn3d.

Tom540

Fri Jul 14 2006, 03:28AM

Banned on 3/17/2009.
Registered Member #487 Joined: Sun Jul 09 2006, 01:22AM
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Posts: 617

This is making me want to mess screw around a little too. I have a few extra secondaries also. One works at around 4MHz and the other 900KHz. It's too hot and im lazy though right now. I'm also gonna be moving in a few weeks so thats my other excuse until I get paid and get more parts.

ragnar

Fri Jul 14 2006, 07:54AM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425

A tesla coil's no fun without an appropriately pretty base... so I whipped this up from some of my single-layer copper-clad (which I can't use for routing boards). =-D

Marko

Fri Jul 14 2006, 12:22PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

BP, I really don't see a reason why don't you build yourself a nice big DRSSTC, with all that copper clad, acrylic, tons of wire and tons of machines to work everything.

I also don't see why don't you like mains ground but I'l let you be.
There shouldn't be any problems if you raise secondary and primary for cm or two.

The problem with bad secondary contact on my SSTC appeared again - this time pressure released itself trough hole on side I used to pass wire in. I caught the first explosion on the pic (I was trying to photograph sparks).

After several failures I fixed it but I know this secondary won't last long after.
Explosion took out about 30 top turns so i'm operating on a bit higher frequency now..

I repeated the shot with just touching the supply, it can be clearly seen what was going on..

Steve Conner

Fri Jul 14 2006, 12:42PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

blackplasma wrote ...

Pwn3d.

Stop being so immature.

BP, nice looking base plate, but I take it you cut those slots to avoid eddy current losses? In which case, they ought to go further in towards the centre, probably.

The 2N7000 thing was intended as an isolated gate driver AFAIK. But it takes a lot to beat the power of UCC3732x.

Marko

Fri Jul 14 2006, 01:17PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Stop being so immature.

But once you grow up, where is the fun

Gate drive really seems not to be so critical with class E. Richieburnett acheived good efficiency by just feeding sinewave to main mosfet's gate.

my and bp's designs are bit different since we are using the primary itself as a choke, and burnett coupled it separately to amplifier.
I don't know if there are benefits in it.

I still can't adjust primary tank circuit to work with unloaded coil. It still gets heavily overdamped. I guessed I need more capacitance but I don't have lots of adequate MKP caps.

Reason seems to be 'too good' impedance match without spark, and coil draws loots of power in this state.

When spark 'loads' it it changes Q and impedance of resonator making class E stage less loaded.
Sorry for writing crap =)

When this resonator dies I'l have either to use a reserve one or wind new, I think I'l want it to be a bit smaller this time, but keeping same resonant frequncy.

Coil emits pretty powerful electric field when there is no breakout.

I held this bulb about 10cm from the coil and it caused a storm of plasma inside.
Heating was so rapid and intense that bulb quivered and cracked in half in matter of seconds.

I guess high toplaod capacitance and very high frequency contributed that too.

ragnar

Sat Jul 15 2006, 03:22AM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425

wrote ...

BP, I really don't see a reason why don't you build yourself a nice big DRSSTC, with all that copper clad, acrylic, tons of wire and tons of machines to work everything.

Hehe, nice try. Couple of problems -- DRSSTCs don't appeal to me as yet, considering I'm broke, juggling school, a day-job that doesn't pay, and my own commercial endeavours in what is an impossible timeframe. The only acrylic I get to use is offcuts. As for the wire, AUD$77 for 7kg of 0.15mm solder-through enamelled copper means I'll never have to buy wire again. I only build small coils, anyway.

wrote ...
I also don't see why don't you like mains ground but I'l let you be.
There shouldn't be any problems if you raise secondary and primary for cm or two.

It's just the frequency that irks me about the mains ground vs return currents, and also the thought that "if I don't actually needa mains ground for this to run satisfactorily, why bother?" -- it tends to introduce noise to e.g. radios on the same circuit.

Any ideas on how I might make the baseplate and/or enclosure for the electronics look a whole lot better? =P

...

Sat Jul 15 2006, 04:58AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

I would paint the copperless places black, then spray it all with a red clearcoat

Putting a nice black painted board (perhapse add a few red or blue/purple stripes if you are in the mood) with the normal colored components for contrast might look cool.

Then add the red primary on a clear or black acrylic former... And some sparks on top

But that is just me...

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