Donald Smith Devices too good to be true

[soundiceuk]

[soundiceuk]

[soundiceuk]

[janost]

I wonder if my mosfet can survive without a heatsink?

It is warm but I can touch it without burning myself.
What would that be? 40-50C?

Are there any drawbacks of running a mosfet at 50Cdeg?

[mr.clean]

OH buddy... haas anyone told you recently, you are so awesome. Similar story, my old computer bit the dust, and lost a lot of stuff, thanks so much for these

[level]

I wonder if my mosfet can survive without a heatsink?
It is warm but I can touch it without burning myself.
What would that be? 40-50C?
Are there any drawbacks of running a mosfet at 50Cdeg?

Don't know what temperature it would be, but if it is getting so hot that you can't leave your fingers touching the tab for 5 seconds or so, then you probably would want a heatsink. Keep in mind that the actual junction is probably quite a bit hotter than the tab. If the tab is starting to get hot, you probably want a heatsink on there. If the heatsink is just cool or warm, to a bit hot, but not super hot, after leaving it running for some time, then you are probably OK.

[mr.clean]

Thank you Janost,

It's an honour to hear from you.

Just to be sure, you mean that I should get a capacitor of over 500 volts or more then? Is it high current or voltage or both that does the damage?

If I place 12 volts at 100 amps onto the plates of a 20 volt capacitor would it explode?


Best regards,

Gary Dunn

hehe, where are you getting 100amps @ 12 v anyway?

[mr.clean]

I wonder if my mosfet can survive without a heatsink?

It is warm but I can touch it without burning myself.
What would that be? 40-50C?

Are there any drawbacks of running a mosfet at 50Cdeg?

could you parallel more to share the load?

[level]

Analysis of Don Smith's dual coil generator demo board

Ok, I took a very close look at those pictures posted by soundiceuk (thanks soundiceuk!) of Don Smith's dual coil secondary electric generator, and after checking very closely, this is what the schematic drawing looks like of Don's dual coil demo board. I know the driver portion is strange and it looks like I must have misinterpreted something, as the the wiring of the NST driver portion of the cicuit with the GDT and pulse cap doesn't seem to make sense, but when I look look closely at how the circuit appears to be wired in the various pictures of Don's demo board, this appears to me to be how the demo board is actually wired in. I didn't count the windings really closely. so the primary might actually be 41/2 or 5 windings instead of 4, and the secondaries might be 17 turns instead of 18, but I can see that both secondaries are wound in the same direction. If anyone thinks I made an error in my schematic drawing interpretation of Don's demo board, please let me know and I will re-examine the relevant photos again to see if I can see what you are saying. I may have misinterpreted some connections, but I think I have it matching the demo board wiring...

As I was saying the way the NST driver circuit is wired in doesn't seem to make much sense, but maybe Don Smith did that deliberately so as to give the general idea, but to leave people to figure out for themself how all it really should be wired in? I tried the NST driver setup wired in as I have interpreted in the attached schematic, using a 1 KV GDT, and the GDT glows orange like a flame instead having a light violet glow when connected in normally. There is also no noticeable output on the secondary, as might be expected.

P.S. I missed the capacitor that Don Smith has across one of the secondaries in my drawing. It appears to go from the center tap to the top terminal on the upper secondary. In other words, right across one of the secondary's terminals, before the diode pair.

[level]

Hi Level,
Thanks for answering. C1 was taken form a television set.Its voltage rating was 1500v and capacitance approximately 220 nF
C2 (the one across the diode bridge) was the one that exploded.
Regards,
Ged

Hi Ged. If you had C2 wired in with the right polarity, then I don't think your capacitor explosion was due to the voltage being applied to the cap. It may well have over heated and exploded because the ripple current exceeded the max Ripple Current rating for the particular electrolytic you were using, as janost pointed out. If that is the case, then you can search for an electrolytic with a higher Ripple Current rating, or lower ESR value. It might have something to do with the way you had your circuit connected in causing the excessive current. Not sure.

[level]

P.S. Speaking of Ripple Current and ESR ratings, I just had a 0.001 uF pulse capacitor fail due to overheating in my sparkgap circuit. I was using one of these capacitors from China:
1000 pF metalized polypropylene film capacitor

It is a metalized polypropylene film capacitor. They have quite a thin body, so maybe they don't dissipate heat very well, but the fact that they get kind of hot in the sparkgap discharge circuit, and I am only driving with about 15W, would seem to indicate that the the ESR is probably quite on the high side.

[mr.clean]

Ok, I took a very close look at those pictures posted by soundiceuk (thanks soundiceuk!) of Don Smith's dual coil secondary electric generator, and after checking very closely, this is what the schematic drawing looks like of Don's dual coil demo board. I know the driver portion is strange and it looks like I must have misinterpreted something, as the the wiring of the NST driver portion of the cicuit with the GDT and pulse cap doesn't seem to make sense, but when I look look closely at how the circuit appears to be wired in the various pictures of Don's demo board, this appears to me to be how the demo board is actually wired in. I didn't count the windings really closely. so the primary might actually be 41/2 or 5 windings instead of 4, and the secondaries might be 17 turns instead of 18, but I can see that both secondaries are wound in the same direction. If anyone thinks I made an error in my schematic drawing interpretation of Don's demo board, please let me know and I will re-examine the relevant photos again to see if I can see what you are saying. I may have misinterpreted some connections, but I think I have it matching the demo board wiring...

As I was saying the way the NST driver circuit is wired in doesn't seem to make much sense, but maybe Don Smith did that deliberately so as to give the general idea, but to leave people to figure out for themself how all it really should be wired in? I tried the NST driver setup wired in as I have interpreted in the attached schematic, using a 1 KV GDT, and the GDT glows orange like a flame instead having a light violet glow when connected in normally. There is also no noticeable output on the secondary, as might be expected.

Yeah you have the exact layout as Don's presented device.

Its a strange thing eh... Logically it really makes sense... But have you also noticed the wicked burns on L2s while running?
...and, the caps do remarkably charge, but cant run anything right off the coils for whatever reason.

So for that reason i went looking at what classic Tesla Coil builders were doing. And as you prob know, there are 2 ways it can work, being :
para cap to series Gap and coil ending at cap,
Or : para Gap to series cap and coil ending at other end of Gap

Both ways seem to give equal output... But #2 para Gap seems to run the primary much smoother and easier

I agree that Don had something deliberately left some things out, or possibly wired as decoys, allowing him to show the device without having to hide it and worry about it ? Idk

In all 3 mentioned methods, the caps DO charge... And can do a wicked discharge explosion for the public.... Whether that was the only purpose i also cant say.

But am having best results with para gap, series cap and coil.

Hey anyone remember Don saying "the smart ones will figure out what im leaving out". ? implying he was admittedly leaving stuff out ?

Lol oh god then there is the direction of turns on L2s... Which again seem to work as +-+- as well as +--+
Although you quickly end up with too much voltage to use if using +--+ but you could just have bulbs in series for the assumed output?
Hehe anyway, great work, maybe the tuning is just so fine, that it will only be a matter of time.
I think all we need are a good variety of tuning caps, and LCR, and no tuning is unachievable

[level]

Done Smith Dual Coil Demo Board - Circuit Replication and Tests

Ok, I connected up a Don Smith center tapped (dual coil) HV air coil transformer arrangement, and drove it with a proper NST driver circuit (not the way Don Smith appears to have it wired on his demo board, which won't work). I am using a 12V NST, and tried with a 0.01UF pulse cap, and then with a 0.1uF pulse cap. I didn't use Don Smith's winding counts that he used on his demo board, but stuck fairly close to Don Smith's rule of thumb of having the primary 1/4 length of the secondary. In my case, each half of my center tapped secondary is about 55 turns, and my primary is about 14 turns, so I don't have the turns ratio exact, but the primary is just a bit longer than 1/4 length of each secondary. I had the center tap on the secondary connected to earth ground.

I didn't rectify the output from the secondaries but just did some testing on the secondaries by testing arcing strength and quality, by testing arcing to a test lead connected to the grounded center tap. Didn't see anything too notable in my testing. Output voltage at end terminals on each secondary winding is not particularly high voltage (not as high as with my same setup using the same secondary wired up in a standard 'tesla coil' arrangment, but the secondary to primary turns ration is less in my Don Smith setup than I had in my tesla coil testing), and although I can get some fairly energetic white arcs all over the secondaries that throw off sparks when I use the 0.1 uF pulse capacitor in the sparkgap discharge circuit (the arcing and sparking is very similar to what mr. clean showed in some of his later Don Smith replication videos), I am not seeing anything that would lead me to believe that results are any much different than just driving my secondary in a tesla coil arrangement.

Analysis:
From what I have been able to gather from looking at pictures of Don Smith's dual coil demo board, the circuit is very simple, and is just a step up air core transformer with a center tapped secondary. Don takes the output of the center tapped secondary and full wave rectifies the output and uses the rectified output to charge some high voltage capacitors, of I believe fairly large value. Aside from the fact that charging large valued capacitors to high voltage can be instantly lethal if the HV cap's terminals are accidentally touched, I was not able to see anything too out of the ordinary going on here. Considering that the circuit is very simple, the only way this circuit could be generating over unity is if somehow the output capacitors are able to be charged with more energy than is being pumped into the primary.

Even though Don Smith initially used to emphasize resonance, he doesn't seem to have gone to much effort to try to achieve it in this circuit other than maybe using his 1/4 length winding ratio rule. Having one capacitor across one of the secondaries, and not across the other secondary wouldn't likely give any kind of matching resonance, and in the Don Smith 'bonus videos' Don said you just need to have the secondary be an even multiple length of the primary, without having to tune the primary and secondaries for an exact matching resonance. I took this approach in my replication setup, and since my primary and secondaries are not in resonance, all I really have is a non-resonant air core step up transformer, with a center tapped secondary.

So, with this arrangement, the only way I can see that you can have more power out than power in, is if somehow this circuit is able to charge the output caps with more energy than being input by the NST driving circuit. Without doing some careful input and output power tests, there is no way to say whether this sort of arrangement can generate over unity, but again, Don Smith's setup for this demo board appears to be just an ordinary step up transformer arrangement with the output converted to DC. A very common arrangement at much lower voltages, and also used in power transmission grids a lot as well, with the exception that this circuit is being driven with high energy capacitive discharge pulses. Now, maybe driving a tesla coil arrangment with high energy discharge pulses does do something unusual, but Don Smith's center tapped transformer arrangment doesn't seem to be generating any more output than an ordinary tesla coil arrangment using the same NST driver configuration, except it uses the center tapped secondary which makes full wave rectification easier, and the output of the secondary is balanced with respect to ground, if that makes any difference.

Did Don Smith have some important secret he left out? Maybe, but in the 'bonus videos', he seemd to be emphasizing that the circuit arrangement can be even simpler and it should still work. I don't want to jump to any conclusions about Don Smith or his circuits, as there may be something key missing that Don Smith kept to himself, but as presented on the demo board we don't seem to have anything too unusual. Just pulsing the primary with high energy pulses and storing the energy in some HV output capacitors. Maybe that is all there is to it, but Don's circuit as is makes doing power measurements tricky. How does the average person make measurements when the output caps are charging to about say 5000 VDC? You need some special equipment to make those measurements, and also a special setup to make use of the energy stored in the HV output capacitors. Again, if you are using capacitances in the uF range for the output caps, they can be instantly lethal at those voltages. Even the pulse capacitors when charged to a high voltage can give a nasty shock...

So, considering that Don's circuit seems to just be a high voltage capacitive disacharge pulse circuit driving a step up air core transformer, and storing the generated energy in some output caps, we should potentially be able to use any such similar arrangment and see over unity if Don Smith's circuits of this type really could produce over unity. Doing tests on similar setups, but maybe stepped down in voltage somewhat, might make input and output power measurements easier. Also, mr. clean's idea of using a solid state capacitive discharge circuit to avoid the problems with all the generated EM noise that sparkgaps make, might make testing even easier.
Good luck in your experimenting.

[mr.clean]

...One thing is for sure, the tuning of primary is 180 khz (if i recall correct) which kinda matches the secondary (assuming air cored) L2 of about 16uH with 47nf and L1 of 3uH or so with 200nf

[level]

Yeah you have the exact layout as Don's presented device.

Its a strange thing eh... Logically it really makes sense... But have you also noticed the wicked burns on L2s while running?
...and, the caps do remarkably charge, but cant run anything right off the coils for whatever reason.

So for that reason i went looking at what classic Tesla Coil builders were doing. And as you prob know, there are 2 ways it can work, being :
para cap to series Gap and coil ending at cap,
Or : para Gap to series cap and coil ending at other end of Gap

Both ways seem to give equal output... But #2 para Gap seems to run the primary much smoother and easier

I agree that Don had something deliberately left some things out, or possibly wired as decoys, allowing him to show the device without having to hide it and worry about it ? Idk

In all 3 mentioned methods, the caps DO charge... And can do a wicked discharge explosion for the public.... Whether that was the only purpose i also cant say.

But am having best results with para gap, series cap and coil.

Hey anyone remember Don saying "the smart ones will figure out what im leaving out". ?

Lol oh god then there is the direction of turns on L2s... Which again seem to work as +-+- as well as +--+
Although you quickly end up with too much voltage to use if using +--+ but you could just have bulbs in series for the assumed output?
Hehe anyway, great work, maybe the tuning is just so fine, that it will only be a matter of time.
I think all we need are a good variety of tuning caps, and LCR, and no tuning is unachievable

Hi mr. clean. Yes, I have been experimenting with both arrangements of the sparkgap and capacitor as well. It was when I put the capacitor in parallel to the NST and the sparkgap in series with the primary that my 0.001uF cap overheated and failed. That might have been coincidence however. The capacitor might have already started to fail when being used in the other arrangement as well. I haven't done enough testing with the two different sparkgap arrangements yet to see if I notice much difference between the two however.

Yes, maybe exact resonance tuning matching between the primary and secondaries is what will make the difference here. Strange that Don Smith only put a parallel cap across one of the secondaries though. That would make one secondary potentially resonant with the primary, and the other likley not. Maybe that has something to do with Don Smith's idea of one side generating voltage and the other side generating current, but who knows?
Yeah, Don Smith might have messed with his demo boards a bit to try to throw people off. Again, not sure what was really going on there...

P.S. I was also getting some burn marks on my secondary coil when I touch the grounded lead to the coil, when I was using the 0.1uF pulse capacitor. There is enough current there that it is basically starting to spot weld. I guess that is why the lead on the neon bulb tends to stick to the secondary coil windings a bit as well. With the neon bulb, the current isn't quite as high as with the straight ground lead, so with the neon bulb lead just sticks a little bit, but with the ground lead and using the bigger pulse capacitor it actually starts burning the secondary winding a bit. There is some current capabiltiy there for sure, but likely only in short bursts since I would think the secondary discharges its energy quickly when drawing power off it. That is the mystery of Don Smith's claims. I can see how you can draw short high power output discharges from the secondary circuit, but how do you get continuous high power out? Something is still missing, or the circuit really can't produce continuous high power out...