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Ignition Coil Question

Posted: Wed Feb 27, 2008 2:41 am
by revans
I have put together a camera circuit as an spark ignition (this one here): http://www.spudfiles.com/forums/high-po ... 10486.html

and have wired it up to an ignition coil as shown in the tutorial (this one): http://www.trademe.co.nz/Browse/Listing ... =142048864

Unfortunately its a bit bulky so I'm looking for a smaller coil. I found this one here: http://www.trademe.co.nz/Browse/Listing ... =141907286

The smaller coil is in a different form factor though so I'm a bit confused. Would it work for the camera flash circuit above?

Posted: Wed Feb 27, 2008 7:03 am
by mark.f
Here's my suggestion: stick with the larger coil. I played around with one of those coils and fried it with only a 12 volt battery, much less a photoflash capacitor...

Posted: Thu Feb 28, 2008 2:36 am
by revans
That's bad, I really need to find a coil that's a bit smaller.

Posted: Thu Feb 28, 2008 5:55 am
by TurboSuper
markfh11q wrote:Here's my suggestion: stick with the larger coil. I played around with one of those coils and fried it with only a 12 volt battery, much less a photoflash capacitor...
That's because it specifically said not to be used with a 12V battery :D .

I Googled about that type of coil, and apparently it's designed to run off a high voltage DC discharge from a capacitor. That sounds like a camera flash to me, although what size cap it should be, or what voltage is beyond me.

Posted: Fri Feb 29, 2008 6:00 pm
by revans
So TurboSuper do you think the smaller coil would work with a camera flash circuit then, seeing as it's basically a capacitor discharge?

Posted: Sat Mar 01, 2008 11:13 am
by TurboSuper
I did some Googling around, and found this:

http://www.next.gr/view-link.php?id=353

This design uses a 2uF cap charged to about 340V.

The cap in a camera flash is much larger, but you can change it easily enough.

The real problem is the 340V; most camera flashes I see only go up to about 200V.

I'm not sure if it won't give you a spark, or just give you a smaller spark.

Posted: Sat Mar 01, 2008 11:19 am
by rcman50166
look up what a marx generator is. That is much more effective than any ignition coil, camera circuit, or tazer could possibly be. And even an idiot could make one! :D

Posted: Sat Mar 01, 2008 12:08 pm
by jimmy101
TurboSuper wrote:The real problem is the 340V; most camera flashes I see only go up to about 200V.
I've looked at several flash boards from disposable cameras and they all charge to better than 300V.
rcman50166 wrote:look up what a marx generator is. That is much more effective than any ignition coil, camera circuit, or tazer could possibly be. And even an idiot could make one!
Not sure how you figure that. You need a pile of suitable capacitors, a fairly large construct to house all the caps and gaps, a voltage supply, etc.
A stungun is cheaper and a heck of a lot simpler. A photoflash is cheaper but a bit more difficult to get to work properly. A photoflash + igntion coil is trivially simple, fairly cheap and much easier to get to very high voltages than a Marx Generator.

Posted: Sat Mar 01, 2008 1:06 pm
by TurboSuper
Oh, well I guess the flash board I had sucked then.

Anywho, it's a trivial matter that can be easily solved with a multimeter in a matter of seconds.

Posted: Sat Mar 01, 2008 5:59 pm
by revans
Thanks for the suggestions. Unfortunately I'm in a country (NZ) where stunguns are illegal so as jimmy101 said my next best alternative is a photflash + ignition coil. Does anyone know if smaller coils like the one linked to in my first post would work with a photoflash instead of the big 12v ones?

Posted: Sat Mar 01, 2008 6:35 pm
by MaxuS the 2nd

Posted: Sat Mar 01, 2008 8:41 pm
by TurboSuper
revans wrote:Thanks for the suggestions. Unfortunately I'm in a country (NZ) where stunguns are illegal so as jimmy101 said my next best alternative is a photflash + ignition coil. Does anyone know if smaller coils like the one linked to in my first post would work with a photoflash instead of the big 12v ones?
Do you suffer from chronic amnesia or something? We've been in the process of answering that very question all day, haven't we?

Posted: Sat Mar 01, 2008 10:28 pm
by revans
Maxus: I have seen that tutorial having searched for it previously and having used it to make the camera flash circuit I have right now. I know there are photos of the circuit being used with a similar small coil but they are not the same as what I linked to and I was merely wondering if anyone who might know of or have used such a coil could give me a definitive yes or no about whether it would work. Cheers.

Posted: Sun Mar 02, 2008 4:50 am
by MaxuS the 2nd
You just need to find the outputs using a voltmeter.

Posted: Sun Mar 02, 2008 1:42 pm
by revans
The outputs of my camera flash circuit? Oh well, I don't have/want to spend money on a voltmeter anyway so can't do that one. Thanks though.