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Cute little FBT

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Adam Munich

Sat Nov 13 2010, 01:12AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

I pulled this out of a 5" tv today. It's a DC FBT and it's the smallest one I've ever seen with an open core. It also has no growths anywhere, so it looks really nice too. Here's a picture of it next to an m&m.

So I was thinking plasma speaker. Does anyonone know of a circuit that doesn't suck? One that won't waste 95% of the energy as heat would be what I'm looking for. I asked this guy for his a few times and he seems to be ignoring everyone. :(

ScotchTapeLord

Sat Nov 13 2010, 01:25AM

Registered Member #1875 Joined: Sun Dec 21 2008, 06:36PM
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Posts: 635

I'm partial to FM via H-bridge. Can't get much more efficient with high power than an H-bridge, and frequency modulation can be passed through GDTs more reliably than PWM! A good chip is CD4047 which is fixed at 50% duty cycle and you can just feed the signal into the VCO pin (using potentiometers to hit the sweet spot with the modulation).

The guy who you linked says he's using a microcontroller for his newer models. I'd be curious to see some documentation on that as well. Not sure how using a microcontroller would be more efficient than just feeding the signal into something that is only a buffer away from the output stage.

I had a FBT like that once. I think I lost one of the core halves, though... :(

Arcstarter

Sat Nov 13 2010, 04:39AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

I love these little flybacks

. I had one like that. I still have it somewhere, actually, iirc. I also have a small LOPT that is verrry weird looking.

As crappy as it sounds... A 555 and efficient power stage is plenty efficient

. It's so terribly simple, but the 555 would not cause any losses. A half bridge or class E output stage would be the way to go for simplicity with plenty good efficiency.

Adam Munich

Sat Nov 13 2010, 05:21AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

I've tried a 555 a while ago, but it failed miserably. Hmm... I'll try it again. I'm going hunting this weekend, but I suppose I could bring my soldering iron to the cabin. ;)

GhostNull

Sat Nov 13 2010, 06:11AM

Registered Member #2648 Joined: Sun Jan 24 2010, 12:45PM
Location: Australia
Posts: 291

I'm looking to build a plasma speaker too, here's what I found:
1.

Jan Martis AKA Dr. Kilovolt's Plasma speaker circuit appears to work quite well.
2.

There are a couple circuits on this thread.
3. Search the forum for Plasma Speaker and you'll get a ton of circuits

btw, Timetec's Plasma speaker has a thread in the projects board or somewhere on this forum.

Good Luck
-Ken

Adam Munich

Sat Nov 13 2010, 06:15AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

I'm just going to try this one because I have all the parts on hand. I'm going to have to order some things for the other ones.

Thomas W

Sat Nov 13 2010, 08:34AM

Registered Member #3324 Joined: Sun Oct 17 2010, 06:57PM
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Posts: 1276

tell me how well that works, mabye a vid?
i plan to make one :)

ubuntupokemoninc

Sat Nov 13 2010, 01:23PM

Banned on 1/22/2011 for repeated rule violations after multiple warnings.
Registered Member #3299 Joined: Sat Oct 09 2010, 08:11PM
Location: Bantown, USA
Posts: 220

nice, i keep getting flybacks with growths so i can't rap thick turns of wire for the zvs , so i have to use thin wire, withs starts smoking if i run it too long

you say you tried the curcuit before? i've only been able too get a 555 curcuit working 1 time, and that was when i bought the chip on digi key, i knew the stuff from radio shack was bad,

try this, that's a nice audio modulator

radiotech

Sat Nov 13 2010, 02:32PM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
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Posts: 1546

Grenadadier wrote " Does anyonone know of a circuit that doesn't suck? One that won't waste 95% of the energy as heat "

A good project would be a combined electrostatic bug zapper,
speaker and air purifier ! That would be a better usage of energy.

Adam Munich

Sat Nov 13 2010, 02:59PM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

@ubuntupokemoninc

You don't need thick turns of wire for a zvs. I used 22awg magnet wire on mine, and I pushed 1.3kW out of the FBT. You should reakky use litz wire though. Look at the inductors on a crt board and you'll see it's braided litz wire. Unwrap them and you have about a yard of it to use for whatever you want.

As for the 555 ic, I have some made by signetics 30 years ago. Maybe those won't die.

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