Build a simple Marx Generator

Step 2 The dangers you must know...

The marx generators are dangerous high voltage generating machines, they produce a pulse discharge of many thousands of volts at approximately 5 to 10 amps! If the spark from the marx generator bites you, your life is over...

There is one thing you must know, a healthy human heart can only withstand electric currents maximum 10mA. Currents over 10mA can results death, I am NOT joking here, this is serous stuff, a lot of people thinks your heart can handle currents up to 500mA, THIS IS NOT TRUE!!! THEY ARE WRONG!!! If you don't believe me, then test your self against a high voltage 500mA power supply, a small microwave transformer would do, put your hand on one lead, put your other hand on the other lead, turn on the power supply and you will be sorry...

The marx generator will also be dangerous after the power is turned off, because the capacitors will hold a lethal charge in them, so, MAKE ABSOLUTELY SURE YOU DRAIN ALL THE CAPACITORS BEFORE YOU TOUCH THE DEVICE!!! Otherwise you will get a 'surprise shock' form the capacitors which can seriously harm you or even death...

Also, every time a marx generator fires (make a spark), it kicks out a lot of UV radiation, and sometimes X-rays! Staring at the sparks form the marx generator can cause problems with your eyes, so wear UV sunglasses or briefly watch it every once a while. If you want to be safe, use laser protection glasses, it will take out nearly all of the UV emitted from the spark and you might not be able to see the spark well, but it much better for your eyes.


Okay, you might be a bit scared after reading this horrible step, so do you think you can build a marx generator? Or find it too dangerous to build it? The choice is yours...

Comments

[endolith]

Can this really harm you? The idea that a special number of voltage or amperage will automatically kill you is not accurate.

Scuffing your feet across a carpet and touching something metal also produces thousands of volts and large currents, but it obviously doesn't harm you, because the capacitance is small and the spark is very short-lived. Yes, it's high voltage and high current, but the duration is less than a microsecond.

I'm sure it hurts, but I'm skeptical that it would actually cause any harm. How long are the sparks in cm?

10x 1 nF capacitors charged to 7 kV store a total of 250 mJ. Scuffing your feet across the floor stores maybe 60 mJ max by comparison.

"The effects of electrical current passing through the human body are covered at length in the International Electro Technical Commission document IEC 479-2:1987. In this document it indicates that a transient or capacitive discharge, as is the case with static electricity, requires energy in excess of 5 Joules (5000mJ) to produce a direct serious risk to health."

[Plasmana]

Okay, you made a very good point, can my marx generator kill? Very good question, personally, I will NOT touch it even if its safe. I never really understand Joules as they are many other units of energy related to it. Each capacitor (1nF) holds approximately 4kV to 5kV, how do I convert that to joules to see if its safe(ish) or not?

[endolith]

I already did that for you, but I was using 7 kV. :) The energy stored in a capacitor is given by 1/2 * C * V^2, so:

1/2 * 1 nF * (5 kV)^2 = 0.0125 J = 12.5 mJ

Wolfram Alpha can do a lot of work for you:

capacitor stored energy 5 kV 1 nF

Multiply by 10 and you have 125 mJ total, which is 1/40th of the energy that document says is the minimum that will hurt you.

I'm not claiming that this thing definitively can't hurt you. I'm just skeptical that it's dangerous. Even if it's not harmful to health, the shock might still hurt like hell. :D

[endolith]

For another example, I'm looking at a safety test certification document for EN 60065, and they limit the maximum energy of a discharge to 350 mJ.

[endolith]

The total voltage could be 70 kV, which means the arcs should be able to jump about 1 inch. Does that seem right?

[chakra]

WOW!! U sure R a expert on electricity!! where u got all those facts from??

[endolith]

I'm an electrical engineer. :)

[tylervitale]

 I've actually read that under certain conditions, as little as 1 mA can be lethal...
D:

[bombmaker2]

I could see that happening, especially if you are very young, very old, or have a pacemaker

[the_lark]

is that doctor octagonapus in your avatar?

[bombmaker2]

Hell Yeah!

[DanRiches]

Remember, Volts Jolts, Current Kills! 40v will conduct nice and easily through you coupled with an amp or so, it'll kill you. A low current at high voltages will cause arythmia also. 1ma at many thousands of volts can kill! Your best bet is to place a high voltage, high ohmic resistor on the output stage and place the marx generator in a protective box. You will not get x-ray from this device, you need a vacuum and a heated heavy metal ie tungsten. You could place an incandescent light bulb which is on near the output and you may generate x-rays within the chamber of the bulb but not in free air. Personally if you are only getting short sharp discharges as in the video then a decent pair of sunglasses will do. Anything more powerful and you may give yourself arc eye, which is very painfull. Yep the device is dangerous, but can be made fairly safe and is a lot of fun to play with, be safe guys and gals!

[jinrowolf]

the death amperage is not the same for every body i taken 15amp's before but you can die from just 10ma

[Plasmana]

15 AMPS through your heart?! How do you even know it is 15 amps too?

[jinrowolf]

not 15amps through the 15amps through my body.

[skrubol]

I'd say sunglasses are better than some random pair of laser glasses. Laser glasses are specific to the wavelength of laser, whereas sunglasses attenuate all wavelengths and good sunglasses should block nearly all UV. Welding goggles aren't much more than really dark sunglasses, and welders can operate in excess of 100A continuous.

[Devenger]

To be fair though, just any old pair of sunglasses won't do much of anything; many pairs of cheap sunglasses are just darkened clear bits of plastic over your eyes. Polarized sunglasses are the only ones that actually filter out UV rays, so be sure to check any pair of sunglasses you purchase for polarization.

Bit of trivia for you: all modern car windshields and windows are polarized, so in theory you could sit in your car all day in full sun, all else being equal, and not get a sunburn (though the heat would be horrific).

[rulo]

Polarization has nothing to do with UV filtering. The reason why car windscreen blocks UV (or in that matter any other ordinary glass product do) is that UV is strongly attenuated by ordinary glass, that is why higher purity quartz is used in UV transmitting surfaces.

[skrubol]

I don't believe this is true. Sunglasses are often rated as UV400, which is supposed to block all UV up to 400nm. Whether it actually does or not on cheap sunglasses is another question. I believe polarization is something completely different, though most polarized sunglasses will also be UV400. Windshields are not strongly polarized. If they were, and you were wearing polarized sunglasses you could turn your head to an angle that would be complete black. Fully polarized glass also cannot pass more than 50% of light. Furthermore I don't think windshields typically do block much UV (standard glass blocks pretty much all UVB and UVC, but not much UVA.) I think you're confusing polarizing with something else.

[afcbasser]

 word.
if your sunglasses say "uv blocking", they're gonna block uv. you can easily test their effectiveness with a fluorescent blacklight.

[Devenger]

No, I'm pretty sure polarization applies here. After all polarization is a way of filtering out all light except for the light that oscillates in a certain direction. Light from the sun oscillates in every direction no matter the wave type, but when it is reflected from a specific surface, it usually oscillates heavily in a single direction, which makes it possible to use filtering by polarlizing lenses. Good sun glasses are made to minimize glare from reflected surfaces; If you look through two polarized lenses, if the polarization of the two is parallel then most light passes through - but if they are perpendicular, then most light is blocked. "Some cars also have polarized windshields for exactly the same reason - to minimize glare from sunlight bouncing off surfaces - like the hoods of other cars. You are seeing light from the inside of a car that is passing through two polarized layers - that of the windshield and that of your glasses, and it is likely that the relative angle of alignment of the polarization between the two is somewhere between 0 and 90 degrees." To that respect, it doesn't matter if its blocking 50% of the light or not; its dispersing the negative UV waves by separating them from the rest of the light wave. "Here is something to try - next time you see a display of polarized sunglasses - hold one pair before your eyes - rotate the sunglasses - and look at all the other polarized sunglasses on the rack as you do so - you'll be amazed to see how all the glasses on the rack turn from clear to opaque as you rotate the pair in your hand."

[skrubol]

I'm not sure what that had to do with the previous discussion. Polarization filters by angle, not by wavelength. Yes, some sunglasses are polarized. My $20 pair are. There are many much more expensive sunglasses that are not. Many people don't like the effect, most who like it use them when on the water. My windshield is not polarized, and I believe the large majority of windshields are not. I believe reflections from glass (and water,) typically are polarized though. Metallic reflections are not very polarized. What's a negative UV ray? UV rays are just like normal light and IR, just shorter wavelengths.

[the "wow shammy"]

how do you drain th capacitors? i don't want to die a horrible death.

[brooklynlord]

You have to drop some conductive thing between the legs of the capacitors. The electricity in the cap with short out and discharge.

[burrejus000]

Did you know that the electric chair ( the one to kill criminals ) is only 2000 volts for 60 to 90 seconds.

[Idonet]

but the inner resistance of some of these cascades may be much higher, so you MAY (!) take 'only' severe burns instead. But I surely will not try out!

[bryanb333]

wow only 10ma i was one shocked by a neon sign transformer rated at 7.5kv 30ma and t was dead shorted before i got me... i still have the scar where it arced into my finger not fun. by all accounts i should be very dead.

[botronics]

When I was in 8th grade i experimented with a 20kv neon transformer my physics teacher loaned to me.  I got a nasty shock from my arm to my shoes.  I was standing on damp cement at the time.  It burned a hole in my sneakers. Even when I was 5, I was sticking paper clips in wall outlet for the cool sparks it made.  Now I design high power circuits for research and industry.

[chemicalvamp]

"turn on the power supply and you will be sorry..." No in fact you wouldn't be, Such high voltage.. High frequency current. is beyond your nervous system's ability to detect. You wouldn't even know you had 2kv passing through you. No time for feeling sorry. You wouldn't know you where dying until you were dead.

[dj_nme]

The spark given off by this is tiny and low amperage compared to an electric welding arc. To stop UV radiation (which is the primary type of dangerous radiation from an electric welding arc) an ordinary pair of clear safety glasses/goggles will do the job, but you will still get eyestrain from the visible light given off and (of course) UV ray-burns to any unprotected skin (think of very bad sunburn). This generator is nowhere near as powerful as an arc welding machine, so there is no reason to expect that normal, clear safety glasses/goggles would not provide more than sufficient protection to your eyes.

[patenaude]

It may be lower amperage, but an arc welder has almost no voltage. While an arc welder provides 100's (sometimes 1000's) of amps, it does it at only a volt or two. At that voltage, your body is effectively an open circuit, and it poses no danger. You could apply the cathode and anode of an arc welder directly to the heart, and the biggest danger would be from infection.

However, 5kV-10kV is serious, and while a static charge on your finger is higher voltage (20kV), it only has a few microamps, whereas this will put out an amp or two of a few milliseconds. Actually, it's producing a 2 inch spark, it must be getting to at least 50kV and probably higher since the breakdown voltage of dry air is 33kV/cm. (It's less for humid air). At that voltage, x-rays are a real possibility, though probably not that many.

[Questioneverything13]

I worked as a welder for years and have never seen a welder that uses a (volt or two) most welders I have used ranged from 15v to 28v some were dc some ac (mig and stick types) in the 50 to 500 amp range but tig welding uses high voltage (2000v+) to start the arc and then the voltage drops.

[patenaude]

I was too glib in my answer, and I don't mean to imply that arcwelding isn't dangerous, but in the case of arcwelding, the danger comes from inductance rather than voltage. A current that high will have a substanstial magnetic field associated with it, and if something interrupts that current, then the collapsing field can cause huge voltage spikes. There will be a relatively "high" voltage to get the current flowing, but once it is flowing, it will usually drop down to a volt or two, but at really high current. However. 40-80v dc usually isn't enough to cause damaning amounts of current to flow through the body. I might be wrong about that, but I've gotten 50v accross me plenty of times, and it was merely unpleasant. -- Mitch

[Questioneverything13]

I agree that the voltage will drop I just didn't know it was that much my welder just shows amps. The open circuit voltage is 28v DC I have never measured it when welding. The emf stuff I totally agree my first experience with it was sitting on a slotcar track as a kid a 12v motor's back emf bites!

[sephiroth9393]

Are you serious? The body can handle a good deal of voltage compared to amps, depending on the path it takes. go ahead and try that with your dad's welder and we won't be viewing anymore posts from you. He's right about the 10mA and it technically only takes about 82 volts across your heart to possibly disrupt it's rhythm. Open circuit or not sh*t happens. All it takes is some water or a small cut.

[TheMadScientist]

poses no danger? people have died while welding in the rain. that's why if you feel one jolt, keep going, two, and you should quit for the day.

[TheMadScientist]

and it may provide only a volt or two, but the arc can be drawn to two centimeters(at max) and that's a helluva lot of amperage.

[Derin]

x-rays only form in arcs made in vacuum,like a lightbulb with nitro-argon gas will spark nicely with only uv,a vacuumed bulb would make xrays and thus glow an eerie green

[Derin]

no,40 volts is the standard arc welder voltage.

[rp181]

its not current that matters. There is no simple way to say" this kills you". Voltage, frequency, and other factors affect it. Generally it takes 16 joules to kill you, not amps!.