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Xray

Mon Sept 05 2011, 10:31PM

Registered Member #3429 Joined: Sun Nov 21 2010, 02:04AM
Location: Minnesota, USA
Posts: 288

ben123324 wrote ...

If you want a "real" Jacob's Ladder, then I would suggest buying an NST.

who says he wants a "real Jacobs" ladder? or even a Jacobs ladder at all? all he said is that he needed a 1-3Mhz 10kV supply for his experiments. a Jacobs ladder isn't really an experiment, its just a display of your arc. you are right, a 60hz mains driven iron core transformer gives a nice hot arc, but that isn't necessarily what he wants.

and Microwatt, for us to help you any further than we have, it would help to know what you are trying to do.

My reply was to Highvoltagechick who wanted a Jacob's Ladder. Sorry you misunderstood my reply. As for Microwatt, I already asked him what he is trying to do, and still waiting for an answer.

H8erade

Mon Sept 05 2011, 10:37PM

Registered Member #3451 Joined: Sun Nov 28 2010, 11:13PM
Location: United States
Posts: 100

Xray wrote ...

ben123324 wrote ...

If you want a "real" Jacob's Ladder, then I would suggest buying an NST.

My reply was to Highvoltagechick who wanted a Jacob's Ladder. Sorry you misunderstood my reply. As for Microwatt, I already asked him what he is trying to do, and still waiting for an answer.

I'm confused. Highvoltagechick wanted a Jacob's Ladder?

Ash Small

Mon Sept 05 2011, 10:44PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

HVC already 'has' a Jacob's ladder, driven by an NST. It does need some straightening of the wires with a pair of pliers, though. And the wood needs replacing with something more suitable. But it is quite impressive for a 'first project'.

Ben Solon

Tue Sept 06 2011, 12:45AM

Registered Member #3900 Joined: Thu May 19 2011, 08:28PM
Location:
Posts: 600

i believe HVC never asked for a Jacobs ladder, she just suggested a plasma globe as the high frequency driver/source. personally i think this is a good idea as long as you don't need much current. i just took a cheap one apart, and it is composed of just a small transformer, a few caps, and 2 semiconductors. i would NOT expect more than a few mA from one. if that's all you need, great!

Xray

Tue Sept 06 2011, 01:13AM

Registered Member #3429 Joined: Sun Nov 21 2010, 02:04AM
Location: Minnesota, USA
Posts: 288

smcerm wrote ...

I'm confused. Highvoltagechick wanted a Jacob's Ladder?

Now I'M confused!!! I confused HVC with the OP (that's what happens when you get OLD!! lol) Anyhow, I read HVC's question, and I looked at her avatar of a Jacob's Ladder, and I thought that she was asking about using a plasma globe for a jacob's ladder. I guess I added confusion to this thread by being confused myself!!! Therefore, I'm going to keep my mouth shut for now and let someone else answer the questions! (I think I need a nap!!! LOL)

Microwatt

Tue Sept 06 2011, 04:18AM

Registered Member #3282 Joined: Wed Oct 06 2010, 05:01PM
Location:
Posts: 224

I believe that you misunderstood what i wanted. A do not need 15khz I need up to 10mhz.

Ben Solon

Wed Sept 07 2011, 08:01PM

Registered Member #3900 Joined: Thu May 19 2011, 08:28PM
Location:
Posts: 600

actually, ~35Khz, but it doesn't matter, its still outside your range. again, we cant help much unless we know what you are doing. it all depends on your application.

Microwatt

Thu Sept 08 2011, 09:25PM

Registered Member #3282 Joined: Wed Oct 06 2010, 05:01PM
Location:
Posts: 224

I am experimenting with ionized gas. A very fast rise time and short pulse width will allow a uniform glow discharge to form.

Ash Small

Fri Sept 09 2011, 02:33PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Microwatt wrote ...

what do you think about using a colpitts oscillator + telsa coil primary: secondary? I am looking for low tech solutions.

I think this 'could' work.

I'd been thinking about some kind of small TC (used spark gap TC technology when I built an HF TIG welder) but the output isn't CW.

I think either a Hartley or Colpitts oscillator should do it. but there could be other problems.

Here is a link to a pdf article about RF transformers:

One problem you 'may' run into is impedance matching.

I'm not sure if this can be overcome some other way in your case, but the one of the problems I ran into when trying to design an impedance matching network for an RF based plasma generator (13.6MHz, in my case) was that you need to be able to calculate the impedance of the load, (ie the plasma itself).

I found some references that suggested that in my case it 'might' be in the region of 2Î© to 50Î©. (this varies from impedance when you turn it on, to impedance of the fully formed plasma). Usually auto-matching circuits are used, but I don't know how applicable this is in your case.

This is the main reason that I'm now planning to use a magnetron for my ion source.

EDIT: A magnetron is driven with DC, up to around 4kV and 'a few' mA. Much easier to implement. (Pretty 'low tech', really.)

Sulaiman

Sat Sept 10 2011, 07:50AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141

I'd be inclined to go for a low power oscillator, a power amplifier
(something like

)
and an air-core transformer with variable coupling.
(something like a Tesla Coil primary : secondary)

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