Sorry I'm being so avoidant. It's a bet between me and a friend. I'm keeping quiet as to the details because he's likely to Google our bet and find this page so he can see how I'm going about it. Silly, I know, but there's pride at stake here!
The short story is that it doesn't really matter what I want to do with it, but how to actually go about doing it.
What are the conditions of winning the bet? How do you plan to measure 30kV?
It's not a bet for who can produce the highest voltage from a 9V battery, so we don't need to measure it.
Treat this as a hypothetical excercise - if you had to create the biggest voltage you could from a 9V battery (or two), how would you do it?
A simple way would be to hook the battery directly to a step up transformer with a push button in between, the push button would have a nice one shot of flux.
Standard issue ignition coil from a newer vehicle can easily do 30 KV. Just use the 9 volt battery to charge up a HV poly cap to a few hundred volts with a old camera flash circuit.
The camera flash circuit may need a voltage regulator to keep the 9 volt battery form burning it up. Some old ones would take 9 volts for Short Burst some wont.
"When in doubt, LIGHT IT ON FIRE AND SEE WHAT COLOR OF SMOKE IT CAN MAKE!" -- tcmtech
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.Originally Posted by Burningmace
Last edited by Space Varmint; 3rd September 2009 at 09:28 PM.
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.
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.
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...
Last edited by arunb; 4th September 2009 at 04:07 PM.
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.
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.
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.
Ask at a place where they develop films, they throw cameras away once they have got the film out.
Last edited by House0Fwax; 4th September 2009 at 05:07 PM. Reason: Spelling error.
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.
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