The Plasma Speaker


Step 2: Schematics

I got the idea from scopeboy's website on his flyback driver section, but the schematic was quite complex and buying four MOSFET's is a little too expensive for me...

So I simplified the design to using one MOSFET.

I get a lot of complainants of this project is not working very well or at all. This new design WORKs, however, for most people it may not work. This is due to the MOSFET (and some other components) is poor quality.

I just recently found out that manufacture who makes the components sell the best quality ones to other manufactures and sell the poorer quality ones to the whole sellers and retailers. For this project, the best grade MOSFET's is critical, and it can only be gotten by salvaging old electronic devices, unless you are willing to pay for thousands of components for the manufacture... :-)
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I replace the MOSFEt with a IRFP4004PBF 40V 350A. Now it doesn't even get warm and the spark i fat. Just a heads-up.
hey what about if a 5 watt amp is placed before the flyback
hey what about if a 5 watt amp is placed before the flyback
Not to be rude or anything, but next to the audio jack on the Schematic where the capaciter is, the Schematic says 47uf 250v but i am finding it verry hard to get one.

I am wondering if you mean 0.47uf or 0.047uf at 250v becuse i am bulding one this weekend (4 days away).

I was also wondering if i could use the cpu cooler from a dell poweredge 1850 server.

Thankyou verry much.
how much voltage are you giving to the flyback coil?(12-40)
im afraid not to burn the mosfet (irf 640)
N3v3rm0r34 years ago
ok, i've built the s[eaker(school project) and.... that bloody mosfet blew up when i was presenting it to the classroom :(. thankfully, i had another one and just replaced it, i haven't soldered the mosfet to any cirquit board, it was beeing held in place by crocodile clips. another thing: would i fix the problem by putting a computer fan on the mosfet??
Just buy a bigger fet, there cheaps as chips on ebay
Make two of these for stereo sound XD
geek101023 years ago
could i use a IRF510A
No, it is too weak for this.
-max- geek101023 years ago
what are the specs on it?
mehdimax2 years ago
dear friends plz help me !
i have ordered a flyback but it doesn't arrive yet ! i have made the circuits but have no clue to test the circuit ..!???

how can i test it when flyback is not in it's place ???????????
waiting for your kind help :)
rather then using high amperage/voltage, use something rather low (but not too low) and put a speaker rather than a flyback in place. Unless you made the speaker, dont worry about the turns.
if this your first flyback project, try something smaller and easier. Not that you cant do it, but because if theres an issue then you will be able to diagnose it easier and definitely safer without giving yourself a good, high frequency, high voltage ZAP. My first project was a marx generator, but because i was inexperienced at the time, i had a problem and no idea what it was - so i gave up and put it aside. it wasnt until over a month later until i gave it a properly improper ground (my body - BIG MISTAKE) and got it working.
anyway, learn about modulation, how to modulate, and why transistors are so important.
then start off by getting a few NE555 timers. Learn how to adjust them to play high and low frequencies through a speaker, and then one day you can connect an audio out to pin 5 on that (hint hint) and make it play sound. then even further, you can put a transistor and a flyback on there and make another plasma speaker :)
email me at anytime:
Couldn't you parallel up more IRF540's to get more power handling capability and then you could share the load between them all?
jaaz953 years ago
can you replace the flyback transformer with a NST and use this circuit in a tesla coil? if so is it even necessary to switch out the flyback transformer?
TimTD jaaz953 years ago
No, because NSTs have an iron transformer core, so they cannot handle frequencies above 1 khz, while flyback transformers have feritte cores and work from about 15khz to 60khz. Since this circuit puts out high frequency, an NST will not work.
I made my the driver on a bread board when i conected it all up....... nothing happend ,The IRF540did't get warm and there was no spark etier
i went over the diagram hundreds of times but it don't work

im frustrated..............................

please help.
jomac_uk3 years ago
Another small point to add if i may, i did a little google because something didn't look right and i wasnt sure what, practically every circuit for an EHT flyback generator had a flyback suppression capacitor across the UF4007

I also tend to agree with electrojohn and his comments.

I had heard of these systems, but never seen one in operation until i saw your video, and was i impressed!!
running 2 mosfet in parallel to help with the load yes you can do it i have ant it helps a lot with heat
st3vvpidvu3 years ago
Can anyone help me? Really confused where the negatives go in the schematics. Is it just connected to another piece of metal to ground the wiring? or connected to the 0v which is hte negative?
Chupy914 years ago
hey N3v3rm0r3 were did you put the negative wire that one for 12-40V.Did you putted on the Mosfet(irf540) and what kind of capacitor did you use 47uF or 47nF?? wainting for your answear:D
Ground is the output for it
jaaz953 years ago
is it a problem if i don't have a 10nf cap? i have smaller and larger but no 10nf ones
jbounce3 years ago
How loud does the music get?
Fenex3 years ago
how many spins in the secondary??
The 47uF 250v capacitor, can it be a electrolytic? With + and - ?
can i use the big mosfet from a CTR computer monitor/TV circuit board, because i have two of them and i want to use them
As long as they are rated at at least 36A and 100V.
No problem.
teche4 years ago
ohh schematics
randomapps4 years ago
here is a design that uses the 555 timer and it doesn't heat up so much 
Can you get a higher-resolution shot of this schematic? I'm having trouble reading the markings for R1 and a few other parts. Thank you
here is the direct link to the schematic
Thanks! This will be a great help. (Very cool web site as well.)
shmolky4 years ago
I'm not sure I understand how the audio connector goes in. Do you just throw the signal line into the mix where the audio jack is and ground the other side?
submanl74 years ago
hey guys my name is dean and i want to have a future in building speakers what kind of stuff will help this fall i will be enrolling in college for electronics engineer and i want all the help i can get
quadrapod4 years ago
I have not read all the comments, nor do I intend to, so if I'm repeating someone else I'm sorry.  but I think your protection diode is in the wrong place, try to put it in parallel with your coil but in tho opposite direction of the flow of voltage.  that way instead of trying to push current through the mosfet when it switches off it will push it in a loop, stopping the voltage spikes.  I will admit I know enough to use a transformer, but I have not quite explored their details, so the hard switching might have some purpose I'm not aware of.
Chupy914 years ago
randomapps can you tell as how to solve the problem ?
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