Generating 30,000V+ from a 9V battery?

[Space Varmint]

One microamp or higher should do the trick, as long as I can produce 30kV or so. The higher the voltage, the better.

Well I forgot to mention that the input voltage of my simple Armstrong oscillator circuit is only 6 volts. So 9 volts in would get you probably 3000 volts out. That's one tenth what you are looking for. You could accomplish the rest by increasing the step up ratio on the transformer and increasing the size of the core (physical & AL permeability) if that's all the current you need.

 

[Mr RB]

I'm with tcmtech, do it the same 2-stage way camera flashes and strobe lights work; charge a cap to a couple hundred volts, then dump the cap into a simple pulse transformer.

 

[Speakerguy]

Stun guns run off 9V and easily generate 30kV, unfortunately they usually use a custom transformer in the design that won't be easy to get. It steps up 9V to about 600V and then they have an arc gap and an output transformer to get it to 50kV or so. You can by a Talon Mini stun gun online for $20 to take it apart and see how it works, it's basically like I've described here.

 

[Burningmace]

Stun guns run off 9V and easily generate 30kV, unfortunately they usually use a custom transformer in the design that won't be easy to get. It steps up 9V to about 600V and then they have an arc gap and an output transformer to get it to 50kV or so. You can by a Talon Mini stun gun online for $20 to take it apart and see how it works, it's basically like I've described here.

Two problems with that:
1) I'm in the UK, and stun guns are classified as offensive weapons. I can't import them.
2) Stun guns produce a large voltage to arc, but once they've ionised the air they drop down to about 5000V.

I'm gonna buy a cheap camera and see how it fares.

 

[arunb]

I think he is trying to make a stun gun of 30KV. I think the loser gets zapped...In any case the project sounds dangerous...

 

[Burningmace]

arunb - If I were trying to build a stun gun, I'd just tell you that I was. Besides, a 30kV stun gun would be lethal if it remained at 30kV. The project is pretty dangerous, but I'm not an idiot - I know how to protect myself from electrocution.

 

[vedo35]

if you can find old scanner take the head. you will see a very thin florecent lamp. you can use that florecent lamp driver. minimum needs 5-6 volts. normally using 12volts. driving bc series(but japan series ones) 2 transsitors and a little hv transformer. i gave also 20 volts working very good. hv jumping from 1 cm distance. if you want you can chance transistors with bd series but you have to chance transformer wires little bit ticker.

 

[Burningmace]

Scanners are expensive and hard to come by these days. Most are scanner-printers. It also seems like I'd have to pull out most of the innards to get it to work. I'd rather build something from scratch or with smaller objects.

I'm heading to the shop in a bit to pick up a disposable camera.

 

[House0Fwax]

I'm heading to the shop in a bit to pick up a disposable camera.

Ask at a place where they develop films, they throw cameras away once they have got the film out.

 

[Roff]

When I was a teenager (50+ years ago), I used a toothed gear from a clock turning against a strip from a tin can to interrupt the current between the secondary (used here as the primary) of an output transformer from a vacuum tube radio, and a 1.5V D cell.. The output of the primary (now the secondary) winding produced an arc that was, IIRC, about 1/4" long. It made a kitten jump about a foot straight up.
I know, cruelty to animals. I wouldn't think of doing that now, but then it was funny.
I now know that it was a flyback circuit.
One potential problem with using a transformer to create high voltages is that, unless it is designed for that purpose, may get damaged due to interwinding high voltage breakdown.

 

[HarveyH42]

Ask at a place where they develop films, they throw cameras away once they have got the film out.

I once got 17 of them for free that way, and still have most of them. The batteries were still in pretty good shape as well. Thing is, they fry pretty easy, around 2 volts if I remember.

 

[Burningmace]

I haven't had chance to get one yet, so I'll ask at my local ASDA's photo processing desk.