Some High Voltage Fun

Just picked up this HV Generator on eBay for $4.20. (Hehe)

NEW DC 3V 6V TO 400KV 400000V Boost Step UP Power Module High Voltage Generator | eBay

Good old Chinese false advertising, 400kV. Lol.

I wasn't expecting much. But wow... this thing was a steal. Easily ~114kV.

Not shown in pics, but I got a maximum distance of around 1.5 inches (3.81 cm) of a nice established spark gap.

Now I'm no electrician but, from what I know DC spark gap voltages are around 30kv/cm, 3.81 * 30,000 = 114,300

Not sure what the practical uses for something like this would be but damn this thing is fun Also loud. It just uses a pulsed output to keep the spark gap going, with a run time of only about a minute. Sounds exactly like a taser(coincidence? I think not) It's very bright, made me want to wear sunglasses or something Definitely wouldn't want to get hit with something like this, I wore insulated gloves while testing, didn't really have to if I was careful but always rather safe than sorry. I would never use this thing without em' :yh:

Just used a couple of stripped breadboard wire for electrodes;



This has got to be one of the simplest circuits I've ever made, all I'm doing is connecting 9v to this thing. I've thrown a toggle switch and a button in with it for when I want specific timing and for when I want it constantly on.





Here it is in action:



I can't remember where but somewhere I heard lasers could be used to direct these spark gaps? If anyone knows anything about that lemme know

oh my i got zapped by those thing before and it didn't feel good......
and those thing can still zap you after power off as that module build up charge and store it in the built in capacitor.

FUBeaches said:

oh my i got zapped by those thing before and it didn't feel good......
and those thing can still zap you after power off as that module build up charge and store it in the built in capacitor.

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I can imagine 114kV going through you wouldn't be the best

And yea, learned that the hard way a long long time ago when I took apart one of those bug zapper things, got a pretty nasty shock... Put my thumb right on the capacitor leads while holding the board.

Curiosity as a kid can be dangerous, good thing my thumb was the only thing that came in contact it hurt for like 10 minutes after tho I remember lol

i used that module to make a shock glove..... and one more thing
that thing can still zap you even when you where insulation such as glove.....due to dia-lectric breakdown.....
the best hing is to never let your body part touch the electrodes.
the zap go through clothing as well..

FUBeaches said:

i used that module to make a shock glove..... and one more thing
that thing can still zap you even when you where insulation such as glove.....due to dia-lectric breakdown.....
the best hing is to never let your body part touch the electrodes.
the zap go through clothing as well..

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Yeah true, still works as a good resistive material. The more protection the better;

Touching the electrodes while it's on and/or charged is a death sentence either way

ElectricPlasma said:

Easily ~114kV.

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You're basing this assessment on what, exactly?

ElectricPlasma said:

Touching the electrodes while it's on and/or charged is a death sentence either way

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No. They voltage may be high, the the source impedance is exceedingly high. I would be impressed if it topped 1mA.

A 9V battery does not have enough power to kill you.

Cyparagon said:

You're basing this assessment on what, exactly?



No. They voltage may be high, the the source impedance is exceedingly high. I would be impressed if it topped 1mA.

A 9V battery does not have enough power to kill you.

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If you read the whole post, I said what I was basing it off of.

ElectricPlasma said:

Now I'm no electrician but, from what I know DC spark gap voltages are around 30kv/cm, 3.81 * 30,000 = 114,300

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I didn't mean literal death sentence, I meant it as a figure of speech meaning it would hurt like a b!tch

wait till you mess with the transformer from microwave those thing will shoot pure electric plasma stream everywhere!!!
hope you get the pun.

FUBeaches said:

wait till you mess with the transformer from microwave those thing will shoot pure electric plasma stream everywhere!!!
hope you get the pun.

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Love the pun :crackup:

I've seen videos on those things, I have yet to screw around with them

ElectricPlasma said:

Now I'm no electrician but, from what I know DC spark gap voltages are around 30kv/cm, 3.81 * 30,000 = 114,300

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No. Just, no.

Air breakdown rule of thumb for ROUNDED high radius electrodes is 10kV/cm. If you are using pointed electrodes it can be as low as about 4500V/cm, but lets use 5k/cm for being generous. So, you measured 3.8cm spark initiation (or did you draw it out to that length?, draw length is a measure of current, not voltage) which with pointed electrodes would be 3.8x5k = ~19kV. This is within the realm of plausibility. If you want to be extra generous call it 20kV.

Output current is likely on the order of 200uA. Totally safe to touch.

Sigurthr said:

No. Just, no.

Air breakdown rule of thumb for ROUNDED high radius electrodes is 10kV/cm. If you are using pointed electrodes it can be as low as about 4500V/cm, but lets use 5k/cm for being generous. So, you measured 3.8cm spark initiation (or did you draw it out to that length?, draw length is a measure of current, not voltage) which with pointed electrodes would be 3.8x5k = ~19kV. This is within the realm of plausibility. If you want to be extra generous call it 20kV.

Output current is likely on the order of 200uA. Totally safe to touch.

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+rep for the info, but please consider the reason I made the following statement

ElectricPlasma said:

Now I'm no electrician but, from what I know

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While I appreciate the corrections you have given to my errors, I would like to apologize for any issues with the electrical information I have posted, and would rather seek feedback on the device itself rather than the technical specifications on it. Not at all trying to argue, I don't know a great deal of this type of content and do accept corrections. Thanks

EDIT: BTW, I measured the gap at 1.5 inches and converted it to cm. Also I've been looking into air breakdown rates, and I've seen a couple sites saying it is 30kV/cm, would you mind providing sources to 5kV/cm?

The difference is in electrode geometry and air composition. With large diameter spherical electrodes (diameter is a large ratio (>x10) compared to gap distance) in 100% dry purified air it is 3MV/m at STP. When you have real air conditions; normal particulate counts at average humidity, it drops down to about 1MV/m with the above electrode geometry. Now, when you greatly increase the electric field density by using small diameter (or sharp/pointed) electrodes it drops the dielectric strength of normal air down to about 500kV/m.

No source on hand and not important enough to me to go digging for one. Not to mention I'm well equipped to empirically test the breakdown voltage of air. Anyway, when two of the forum's most knowledgeable veterans in the EE field point out the same thing, it's usually a safe bet. Mind you, I'm not knocking you; you didn't know better, and asking for sources is always a good thing with internet information. In this case the sources are rather obscure as it's not something most who deal with electronics run into. High voltage engineering is a lot like RF engineering; the normal conventions go out the window and data isn't easily found outside of academia.

ElectricPlasma said:

If you read the whole post, I said what I was basing it off of.

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I apologize, I somehow missed that sentence.

Wikipedia does say "The dielectric breakdown strength of dry air, at Standard Temperature and Pressure (STP), between spherical electrodes is approximately 33 kV/cm." However, you do not have spherical electrodes, and your air is not dry. A real-world approximation is closer to 10kV/cm from what I've read. This is because corona discharge of a non-spherical electrode partially ionizes the air. Sigurthr may be correct. I've got a 30kV meter and I'll test this out later if I remember.

I have a couple of these round China Tazers as I like to call them .

I can confirm they give you a hell of a crack if you touch them. Most of the pain came from the frequency of the discharge, which speeds up as the electrodes get closer and reaches a peak of around 1-2Khz.

I ran the experiment. We can quote sources all day long, but nothing beats an actual experiment:

Cyparagon said:

I ran the experiment. We can quote sources all day long, but nothing beats an actual experiment

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Nice! Thanks for the vid. I guess generally it depends on air conditions; but looks safe to say 10kv/cm is a solid rate for average conditions