50kV sparks and plasma from ignition coil.

[alex681219]

I use an old audio oscillator, i think generates sinusoidal waves , theres diference in the performance vs. square waves?

[decod31]

@alex681219 In general yes since the spark is formed at the moment of sudden switch off which results in a voltage spike of around 500V which transformed by 100:1 gives you 50kV. Sinusoids don't have that sudden switch off. Not to mention they aren't very good for switching mosfets on and off anyway. If you were to drive the coil directly as a transformer you would need quite high voltage to begin with.

[alex681219]

@decod31 My audio oscillator is a HP200AB model 1950, I think that maybe produce square waves because my ignition coil works fine (8mm) sparks with single toshiba 2n3055...I will try to conect my granpa oscilloscope to see the real wave form.

I have a Motorola mjl21194 transistor, I read that is beter (many bedinis and backEMF collectors use that like ellite transistor)but expensive $ 8 vs $ 2 dollars 2n3055, what you recomend try to fry $8?

[decod31]

@alex681219 Sounds like your audio oscillator might be quite powerful and drive the transistor to saturation and possibly switches it off quickly due to saturation giving you more square wave like waveform. I wouldn't risk the $8, it's unlikely that much better. Audio drive in general is somewhat inefficient, but will work given enough power. Mosfet (IRF740 should be less than $2) with square pulses gives better bang for the same power, but whatever works... ;-)

[southernclassik]

Sounds like little farts.

[decod31]

Hmm, never thought of it that way, probably because I heard live how loud it was, but now that you mentioned it... ;-)

[lazzer408]

n-ch mosfet gate drive is simple. Pull the gate to source with ~10k and a 1-3ohm resistor in series will help interference. Drive that with a 2 transistor totem-pole. wa-la.

[nicholaswheeler]

i dare you to put your finger in there

[98209276]

how do you controll voltage spikes and feedback this common thing detroys most of my timers and transistors im trying out a 0.1uf cap in series with a 10k resistor to cut down feed back but i want to make sure as the circuit i have built cost me $30.00 and i dont want to break it its a wave generator could you suggest some sort of high voltage switch or gate to stop feedback please thank you very much for any help i would much appreshiate it.

[decod31]

I didn't really have problems with spikes so I used pretty much nothing (besides one parallel capacitor). The spikes depend heavily on the conditions (coil/components/connections). I added some more info to the description.

[decod31]

I recommend you read the description of my video "Ignition coils can handle quite high power levels". It has more info about the spikes. Making everything optimal can be tricky.

[decod31]

BTW. typical way of protecting the control electronics from spikes is to connect two ultrafast diodes from the signal wire to posive and negative power supply rail of the control electronics so that anything exceeding that voltage will be shorted through the diodes.

[decod31]

In addition two signal transistors (2N3904 & 2N3906 for example) in half-bridge arrangement with small resistors amplifying the 555 signal before the MOSFET gate would also serve to isolate the control electronics from the switch.

...However I don't think this is really that difficult...

[decod31]

0.1uf cap in series with a 10k at the gate is not a good idea. That is not the way this circuit is ment to operate. MOSFET gates are capacitors and will switch-off too slowly and will not build sufficient current if operated such a way. Not to mention million other problems... That will not work for bipolar transistors either because sufficient current amplification will not happen with 10kohm resistor. Bipolar transistor equivalent circuit would require additional current amplification stage.

[98209276]

thankyou very much im glad you told me this otherwise my wave generator might be screwed ill try using a mosfet in my design, would one of those big tv mosfets be good they usually work around high voltage and have heavy switching capabilities and so on.

[decod31]

Possibly. I don't know what kind of MOSFETs you have. I used IRF740 which is a relatively fast one with 400V max voltage handling and 10A continuous current with 40A peak. But you don't need that much current handling necessarily. Voltage handling is more important. This video was below 10A. The parallel capacitor is rather important. Non-electrolytic 100nF/400V is probably safest.

[98209276]

can you link me to the plans?

[decod31]

Links were already in the description. I used just the "basic circuit". However I added an example 555 schematic link to give you an idea about the security measures. Google has good 555 timer circuits.

[98209276]

thanks

[fdoca]

So, what you think is batter way?

you offer no solution

[wildhart7]

one word MOV lol metal oxide varistor , get one!

[BenHutchinson1]

Neat! But, why do you (and many others as well) use a hard to find power transistor like a power MOSFET? I use a very easy to find power transistor, the 2N3055 NPN power transistor. You can buy one at Radio Shack for just a few dollars. I have NEVER seen a power MOSFET at Radio Shack.

[decod31]

Simply, they aren't hard to find everywhere ;-). They cost only about 1 eur and are easy to drive (infinite current gain at DC) and can handle huge voltages (IRF740: 400V) and currents (IRF740: 40A pulsed, 10A RMS).

[segarza]

He's trying to steal your viewers like he does on other videos I've seen. He's just advertising his website.

[hartiberlin]

overunity dot com is a research site where also

unusual energies are researched...

Like Steven Mark´s TPU etc...

Was just a tip for your readers to mightgo there and see other interesting experiments also with high voltages ! Thanks . Regards, Stefan ( admin overunity dot com)

[hartiberlin]

Please come to overunity dot com to discuss this

setup.

Many thanks.

Regards, Stefan.

[decod31]

Sorry, I don't want to be associated with crackpot sites. Overunity looks like one. This setup has nothing to do with overunity or perpetual motion. Actually I don't believe anything will ever genuinely be. I'm happy to discuss it here however.

[bodziobran]

does ignition coil have any resonant frequency in which spark is strongest and power dissipation from mosfet lowest ?

[decod31]

They definitely have one or perhaps couple of resonances. That frequency is different for every coil however, in my experiment lowest resonance has always been in the kHz range. The resonant frequency is not the only thing that determines the spark length however. You can push more current with same voltage when using lower frequencies so you get fewer sparks, but they are longer. Resonance is good for streamers, but high current low frequency is good for spark length.

[bodziobran]

Could you post what was minimal current obtained in this experiment ? What is the minimal current required for spark from ignition coil ? I have one motor pulse regulator but with current limited to 1A - could it work as a driver for ignition coil ?

[decod31]

Minimal current required for sparks depend heavily on the spark length. I can't measure that right now, but as far as I remember the longest spark I made with this rig required a peak 10A of current pulsed from a capacitor, power source was only 2A/24V/DC. With 1A you can however get short sparks, but nothing like seen here. Pulsed current is the way to go here. 1A is however enough for the lightbulb experiment where resonance is used.

[decod31]

Perhaps it's useful to explain more what goes on here. I pulse as high current as I can to the coil and at the peak current switch the current off as fast as I can. Inductive kick then gives the sparks. You need to remember to protect your switching device. Effective frequency is perhaps 100Hz and it is not the resonance F. In my lightbulb experiment I do use resonance, but it's air sparks aren't actually this long, only the plasma sparks inside the lightbulb.

[Atomic101Heli]

Sir i have a qustion i have a weed whacker ignition coil and want to do stuff like u do make it arc out now i dont have a clue how do that! and its a weed whacker ignition it works if u could help ples!

[decod31]

Weed whacker coil is probably mostly similar to normal car coil. I added the circuit I used to the description, just try that. Basic idea is to give the coil some current and the quickly disconnect it. Semiconductors are needed for good results.

[Atomic101Heli]

Can you tell what to by cause i dont have an ociliscope do i need one?

[decod31]

You don't need oscilloscope necessarily. All needed parts are listed in the schematic (10nF capacitor, 24V supply, IRF740 or similar MOSFET, signal generator + connectors and boards naturally). Power source should be at least 2A (DC). Google for 555 timer circuits instead if you don't have access to function generator.

[Atomic101Heli]

I have most of those parts out of an elctronices kit from radio shack THANKS for your help sir! i will start building!