Plasma Speakers

magnet18

Joined Dec 22, 2010
1,227
and POP goes the MOSFET.

Sorry!! then this is something I would not prefer to make.
I realize it just ain't worth the trouble.

But it is good for a show or like carnival or something
To clarify, I WAS abusing my little FET.
It was a somewhat weak FET, and I had it at about 40kHz, 70% duty cycle, no dampening resistors, and it was the only MOSFET.
If I had used a High-side/Low-side driving setup at a lower duty cycle using a sizeable MOSFET I could probably get a good volume from the thing.

I plan to make a setup that works well with parts avaliable from radio-shack/goodwill/hardware store so that more people will be willing to build these, but it's a ways off
 

kubeek

Joined Sep 20, 2005
5,794
magnet18: Just a side note, do you realize that half-bridge useless on a standard tv transformer as it has the rectifier inside, so you can´t rectify the other half of the pulse?
 

magnet18

Joined Dec 22, 2010
1,227
magnet18: Just a side note, do you realize that half-bridge useless on a standard tv transformer as it has the rectifier inside, so you can't rectify the other half of the pulse?
I'm not entirely sure, but I think that can be overcome by 2 ways, either use an older AC flyback, or use this type of half-bridle


Not my design, but it's what I meant when I said half-bridle.
I apologize if my terminology is incorrect, if so please tell me what word I should be using :rolleyes:
 

kubeek

Joined Sep 20, 2005
5,794
That is still a normal halfbridge and it is useless without access to the secondary AC.
The problem is that a flyback stores the energy when the switch is on and relases it when it is off so the current always flows in one direction, but the halfbridge stores and releases energy on both polarities and thats why it needs fullwave rectification and not halfwave like in flyback.

Running a flyback transformer like a half-bridge will probably not burn anything, but it won´t help either.
 

magnet18

Joined Dec 22, 2010
1,227
You'd be correct there, my bad.
Now you've got me thinking about winding multiple primaries... I'll think on this some, maybe make a new thread, but let's not hijack R!f@@'s.
 

Thread Starter

R!f@@

Joined Apr 2, 2009
9,918
Now you guys have done it.......you posted a HV schema..soon the n00bs will be jumping in on it...Wait and see how long this thread get locked.

By the way I will be honored if you would continue your discussion in this thread...just send the schematic's into the PM.
This way no one can make any and or kill something in the process.
 

Thread Starter

R!f@@

Joined Apr 2, 2009
9,918
You must have misunderstood me.
I said PM because then the schema will be in responsible hands.

They won't be accessible to the wannabes, if you know what I mean.

I too don't want anyone getting hurt.
And yes, I did know about that thread. I wonder why it is not locked.

So I guess the purpose of this thread has been fulfilled.
 

jpanhalt

Joined Jan 18, 2008
11,087
Looking back at it I'm not sure why my threads never got closed.
I guess they must like me :D
Nah, I think it is just the spirits of engineers past who protected you. At least your name is associated with some well known aeronautical engineers. Ever hear of Michael Selig or Donald Fraser at home? They studied low-speed airfoils too. Selig's airfoils were particularly popular for high-performance sailplanes. I guess wind turbines are pretty similar.

John
 

magnet18

Joined Dec 22, 2010
1,227
Nah, I think it is just the spirits of engineers past who protected you. At least your name is associated with some well known aeronautical engineers.
What, my real name? Pope? How?
Ever hear of Michael Selig or Donald Fraser at home? They studied low-speed airfoils too. Selig's airfoils were particularly popular for high-performance sailplanes. I guess wind turbines are pretty similar.

John
Selig rings a bell, nothing beyond that that I can really remember.
 

jpanhalt

Joined Jan 18, 2008
11,087
You mentioned once that your dad was an engineer. Purdue is a excellent engineering school (I vaguely recall that Selig, Donovan, or Fraser -- its David Fraser, not Donald --did some work there, or maybe it was U. Illinois (?). I have their book, "Airfoils at Low Speeds," Soartech 8, H.A. Stokely, Virginia Beach, VA, 1989. It's been well used. Don't get me started on airplanes. I literally went without food so I could buy them.)

Anyway, I came across the following aeronautical Pope's:

Rae, W. H., Jr., and Pope, A., Low-Speed Wind Tunnel Testing,
Wiley, New York, 1984.
Pope, A.,'Basic wing and airfoil theory', 1st ed. McGraw-Hill,
New York, 1951.

Given that time span, if A. Pope is related, I figured one might be your grandfather.

John
 

magnet18

Joined Dec 22, 2010
1,227
Hmm, my dads the genealogy buff, But from what I've heard, my grandfather died in nam and he split home ASAP because his dad wasn't too nice, but I may be getting things mixed up.
In any case, were ALL named Robert, and I think noone before my dad went to college, not sure though.

And now that you changed the name, David Frasier rings a bell also.
I remember a couple years ago we saw someone on TV that my dad used to work with at Lockheed. My dad himself ended up leaving the field fairly soon after entering it and went through medical engineering and stuffs and eventually ended up in trucks.
He always did say that the aero engineering at Lockheed was what he liked most though.
 
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