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LIGHT

Fri Nov 26 2010, 04:15AM

Banned on 4/6/2011 for unsafe, irresponsible behavior.
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Hey guys, I just signed up to this community as it seems full of knowledge.

I took a small transformer out a CD player, and I put 12v on the secondary coil, acting as a step UP, transformer, and it produces a small spark of plasma, but I has to rapidly touch the terminal of the supply to get the sparks, I cant hold it on and make sparks, how can I make it produce sparks with just putting the - and + terminals on the transformer without me having to touch the cables on rapidly?

Thanks in advance!

Ruben

Fri Nov 26 2010, 04:36AM

Registered Member #3263 Joined: Sat Oct 02 2010, 04:43AM
Location: Sydney, Australia
Posts: 34

A transformer only operates from AC (or pulsed dc, as In your case). You may be able to find a simple, two transistor inverter circuit to get a few hundred volts out of your transformer. Much more and the secondary (240v primary) won't hold up for long.

I would recomend you get yourself a flyback transformer, or a car ignition coil, and build one of the many, battery powered driving circuits (hvwiki or google search)

cheers!

Ash Small

Fri Nov 26 2010, 07:42AM

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

This is the simplest circuit for driving a flyback, it only has one transistor. You will need a decent heatsink though (I found out the hard way).

You'll probably find it on a few other sites if you google 'single transistor flyback driver' if you want to read more about it.

IntraWinding

Fri Nov 26 2010, 02:52PM

Registered Member #2261 Joined: Mon Aug 03 2009, 01:19AM
Location: London, UK
Posts: 581

You need to interrupt the DC current frequently to get a more continuous spark. Surprisingly the very rapid change of current produced by just touching a wire on and off a battery can produce voltages that are hard to beat with more sophisticated electronics so you might like to try this. See if the transformer produces a strong enough 'external' magnetic field to attract something made of iron (a nail or whatever). If it does you can use this to make a kind of 'buzzer' that switches the dc current tens of times per second. The trick is to arrange things so that when you switch on the power the transformer causes a magnetic field which attracts the iron and this pulls open a pair of contacts which break the connection to the transformer. At that point the magnetic field disappears (you get a spark) and if the iron is set up right, it will spring back to remake the contact and start the process over again. You'll be able to tweak it to get the best spark out. Search Google for how a door bell or buzzer works if you need more details.
You shouldn't need reminding at this site, but I'll add that you need to be aware of the potential dangers of high voltages. I've had a really shockingly powerful jolt from an ordinary low voltage door bell in the past just from its 'back EMF'!

Steve Conner

Fri Nov 26 2010, 03:20PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

You can actually connect the primary up to a bell, buzzer, car horn, etc. What you've made is just a version of the age old "Model T Spark Coil".

When I was a kid I used to make them out of relays. You can wire a relay up so that it buzzes, and then connect the primary of a step-up transformer across the relay coil, and give yourself a really good jolt that way. :O

LIGHT

Fri Nov 26 2010, 06:52PM

Banned on 4/6/2011 for unsafe, irresponsible behavior.
Registered Member #3442 Joined: Fri Nov 26 2010, 04:09AM
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So what do I need to make it pulsed?

And where can I get one?

PS. Thanks for all the replys.

radiotech

Fri Nov 26 2010, 07:03PM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
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You could connect one of the sparking wires to a file, like
a metal nailfile and just scratch the other wire across it.

LIGHT

Fri Nov 26 2010, 07:49PM

Banned on 4/6/2011 for unsafe, irresponsible behavior.
Registered Member #3442 Joined: Fri Nov 26 2010, 04:09AM
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Anything better than that?

Saz43

Fri Nov 26 2010, 08:57PM

Registered Member #1525 Joined: Mon Jun 09 2008, 12:16AM
Location: America
Posts: 294

walshy155 wrote ...

Anything better than that?

Try the single transistor driver, as previously suggested.

LIGHT

Sat Nov 27 2010, 01:28AM

Banned on 4/6/2011 for unsafe, irresponsible behavior.
Registered Member #3442 Joined: Fri Nov 26 2010, 04:09AM
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OK but I'm kinda a beginner with electronics, can you show how I do that?

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