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Electronics => Electronics => Topic started by: hazzer123 on April 09, 2007, 12:48:55 PM

Title: Coil gun - battery
Post by: hazzer123 on April 09, 2007, 12:48:55 PM

Hi

I have made a small, 1 stage coil gun using a disposable camera. What will happen if i put a 9v battery across the terminals? Will the capacitors charge at a higher voltage, or will they just charge more quickly?

Thanks

Harry

Title: Re: Coil gun - battery
Post by: Somchaya on April 09, 2007, 02:50:05 PM

Hmm.. I'm not very good with electronics, but I think it'd help a lot if you can post your schematic so that others can have a look and have an idea what you mean exactly by putting the 9v battery across the terminals..

From what I think I know about capacitors, they have a maximum charge that they can store, so increasing the voltage may not necessarily increase the voltage on the capacitors.. I'm not sure what happens when the voltage you supply is over their maximum though..

Title: Re: Coil gun - battery
Post by: ed1380 on April 09, 2007, 02:58:51 PM

The terminals where the AA battery goes?
If so it probably won't be good, since the 1.5v already goes through a transformaer that turns it into 280v (280 is what my disposable camera cap said)
so 9v times the SF rating on the transformer(185)=1665v
IIRC caps actually explode

Title: Re: Coil gun - battery
Post by: hazzer123 on April 09, 2007, 03:03:15 PM

Ahhh ok. I was just checking if the transformer will step the voltage up hugely, or just increase the current. Oww welll, how could i improve the charging rate of the capacitors?

Oh and how is this DC current being stepped up? i thought only AC was transformable...

Thank you

Harry

Title: Re: Coil gun - battery
Post by: ed1380 on April 10, 2007, 02:39:09 PM

no clue
<----noob

Title: Re: Coil gun - battery
Post by: Somchaya on April 10, 2007, 02:44:56 PM

Hehe, so I got pretty intruigued by how the stepping up would work, and I found this:

http://electronics.howstuffworks.com/camera-flash2.htm (http://electronics.howstuffworks.com/camera-flash2.htm)
http://electronics.howstuffworks.com/camera-flash3.htm (http://electronics.howstuffworks.com/camera-flash3.htm)

So apparently, the camera has a little oscillator that gives the coils bursts of DC voltage, which causes a changing magnetic field, etc etc..

I'm not too sure of the specifics, but I think the site explains it pretty well :)

Title: Re: Coil gun - battery
Post by: Hal9000 on April 10, 2007, 03:57:20 PM

http://www.hackaday.com/2007/03/21/make-a-small-coilgun-aka-coilosapien-update/ (http://www.hackaday.com/2007/03/21/make-a-small-coilgun-aka-coilosapien-update/)

Is this the stuff you're looking fo' ?

Title: Re: Coil gun - battery
Post by: zamboniman60 on April 10, 2007, 08:41:33 PM

You can't store any more voltage in the capacitor than the oscillator circuit already gives it through the transformer, because these things are designed with next to no headroom. If you want to increase the power of your coilgun, you may find it useful to use a few car batteries -- those things can pump out insane amounts of current.