well, i decided that id make a jacob's ladder. I don't have a step up transformer, so i yanked a step-down transformer out of some piece of electroncis and connected it backwards.

the math that i did to find how much the transformer was outputing was this: (the tranformer stepped down the voltage to 4 or 4.5 or something) 120/4= . . . 30x120=3600 volts. of course i have noo idea of the "right math", but I figured this would work . . . does it?

another thing im wondering is, is it allright to connect transformers backwards? Cuz when I did this, the transformer hummed really loud, made some smoke, and then tripped the circuit breaker on my little power strip :lol: .

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I remember an article in Nuts and Volts about building one of these. It used a coil for a car engine, an IRF -530 transistor, and a 556 timer IC I think 2 555's would work. You just used 2 pieces of coat hanger on the coil as the ladder.
I couldnt really get it to work, my local radioshack only had the IRF 510. I would get an arc, but it didnt have enough power to it, I think my PSU unit was junk though.

Sorry I dont have a schematic or anything, but the 12V automotive coil is a very good start. Almost every automotive place should sell them. It's just a coil for an older car with a distributer. it was only about $12 too.

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To the optimist, the glass is half full.
To the pessimist, the glass is half empty.
To the engineer, the glass is twice as big as it needs to be.

 

It's often ok to use a transformer backwards, but not when you're making sweeping changes in the voltage. For one, the output does not have the insulation to sustain the high voltages generated.

Line freq neon sign transformers work great, but they are an electrocution hazard.

You can make a little Jacob's ladder with a TV flyback hooked up as a (do I have this right?) Hartley oscillator. It's high freq and considerably less deadly, though it will burn you. And yes, many use an ignition coil.

 

Hi Zach,
Please don't connect anything to the mains unless you know what you are doing, certainly not a backwards transformer like that, nor a car's ignition coil nor a TV's flyback transformer.
When I was a kid I plugged a bare NE-2 neon bulb into the mains. It disappeared with a bang, and I'm lucky that my vision and fingers didn't disappear too.

Hi Oz,
Electrocution Hazzard?
A store near me has neon all around the window. On the windowsil inside, easily reached by anyone, especially children, are three 12KV/30mA transformers with exposed HV amd mains binding posts!
The owner just laughed when I explained the hazzard. How can I demonstrate the hazzard to her without making her disappear?

 

Hi Zach, Transformer Windings have Inductance which creates "Inductive Reactance". This Inductive reactance is simular to a Resistance but it is also changes, relative to Frequency.

Transformers are wound with a specific number of turns and Wire Sizes, relative to the Voltage, Current Required and the Frequency.
You Can't just connect ANY winding to a line voltage. It can Become EXTREMELY DANGEROUS to do so.

It is also Not Recommended to use 50 hZ transformers on a 60 hZ line, or Visa Versa. They will not blow up, But the will not Deliver the same Current Rating.

Gary

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Let her reach in (just like a kid might) and touch the exposed mains (across hand with no path through body of course).

If she won't do it, why not? You could also explain the liabilities and lawsuits that would proceed should someone get injured by it.

 

well, i wasnt all that serious about the whole thing . . . i didn't plan to put that much effort into it :lol: . i was just havin a bit o fun.

im pretty safety conscious. I hid under the table and plugged it in :lol: .

Could you make some sparks and arcs fly for a little demonstration?

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http://www.vk2zay.net/article.php/13
Zach you will like this site..
He uses a marx Generator, to generate very large Sparks..

 

hey willi, how in the world did you end up digging up that topic? its really old!

Hmm, yes, marx generator, just another thing on my to-do electronics list :twisted:

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I wouldn't really trust you with too much of my line powered electronics :wink:

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Wuddya mean by that? i wouldnt experiment on expensive gear :lol:

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I'm no electronics god, i just talk too much.

 

oh I own fewer working electronics than butchered PC boards . :wink:

if anything you wouldn't want me anywhere NEAR your electronics gear.

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haa, sounds quite a bit like me!

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