Question about Gate Drive Transformer

Thread Starter

magnet18

Joined Dec 22, 2010
1,227
Hi,
I'm currently building the plasma speaker found here
http://teravolt.org/Plasma_Speaker_2.htm
Instructable here
http://www.instructables.com/id/A-reliable-plasma-speaker/step2/Making-the-GDT/
And I had a question about the GDT, Which is driving IRFP250 MOSFETs.
It says that it is 14 turns of 22ga wire,on a 2.5cm ferrite; I was unable to fit that number of turns of a ferrite of that size, and was wondering if 8-9 turns would be acceptable to get it to work? I've attached some pictures.

I don't know all that much about MOSFETs and less about transformers, and wanted to be sure, or at least somewhat sure, that it will work before wiring everything to it, or if I should just try again.

I would ask on the instructable, but the question has already been asked and it appears the author's only response is to fiddle with it. I seem to lack the coordination to wrap one of these in anything under n hour, so I'd rather not do that.

Here's the schematic


If anyone knows enough about this to tell if it would work or knows of any good sites that deal with calculating this for beginners (other than the textbook here) I would greatly appreciate it.

Thanks in advance :)
 

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Thread Starter

magnet18

Joined Dec 22, 2010
1,227
You also might have noticed the plastic spacer under it, is that a bad idea? If not, would it be a no-no to run any wires through there?
(yea, I'm n00b)
 

SgtWookie

Joined Jul 17, 2007
22,210
He used AWG-24 wire from a Cat 5 cable, not AWG-22.

If you don't have enough turns on the ferrite core, you won't get as much output current due to the lower coupling.

Don't bother with the spacer. Once you have it working, just use a hot glue gun to secure the toroid to the board.
 

Thread Starter

magnet18

Joined Dec 22, 2010
1,227
He used AWG-24 wire from a Cat 5 cable, not AWG-22.
OK, that makes sense

If you don't have enough turns on the ferrite core, you won't get as much output current due to the lower coupling.
So then I should re-wrap it with smaller wire?

Don't bother with the spacer. Once you have it working, just use a hot glue gun to secure the toroid to the board.
I just had it there because it was easier than trimming the wires. :p
 

Thread Starter

magnet18

Joined Dec 22, 2010
1,227
Only if you want sufficient current to drive the MOSFET gates.
Thats a yes then, sorry, your first one said less, I wasn't sure how much less...

I'd like to re-wrap it anyway and use some nicer colors :)

Thanks for the tip on mounting it :)
 
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