how to make a small, powerful transformer

[monboy10]

hi i was wondering how to make a small(about pockets sized) DC transformer that can make a spark from 1 or 2 aa or aaa batteries (1.5v each) and it also has to be safe.

-thanks for the help

[Ron W3FJW]

How large a spark?

[earlwb]

many many years ago we did this using a 6v lantern battery, but the a single little AA or AAA battery doesn't have the current capability. One ought be able to get a series of 4 nicad AA battery to last a while at high current to drive the transformer.

You can buy a small ignition coil setup for a old timer free flight engine like this shown here: http://www.modelflight.com/ignition.html
You should be able to get a number of sparks from the coil before the battery goes dead. Think four AA nicads in series.
small ignition coil http://www.jerry-howell.com/ModelCoil.html
ignition module http://www.jerry-howell.com/IgnitionModules.html

Now if you want to really make the ignition coil:
http://members.misty.com/don/trigcoil.html
The primary probably has about 20 to 30 turns of 22 to 26 guage wire.
The secondary high voltage coil has about 3000 turns on it using 30 gauge wire. Maybe more.

[rich smith]

hi i was wondering how to make a small(about pockets sized) DC transformer that can make a spark from 1 or 2 aa or aaa batteries (1.5v each) and it also has to be safe.
-thanks for the help

A regular low voltage transformer with 1.5v battery on the secondary works good. The lower the voltage the better. Old radio speaker transformers were best. Great for walking around the schoolyard with a buddy giving "handshakes".

[monboy10]

a 9 volt battery would be good to

[monboy10]

how high of voltage do i need you get a spark? because i was thinking of somthing like this http://www.instructables.com/id/How-to-build-the-Worlds-Smallest-Electronic-Shock/

[eflightray]

Hope you read the following in that link -

"Disclaimer: This shocker can be dangerous, it gives out 450 shocking volts, so I am NOT responsible if you or anybody are injured or killed by the shocker, the responsibility is yours..."

[jeffs555]

how high of voltage do i need you get a spark? because i was thinking of somthing like this http://www.instructables.com/id/How...ectronic-Shock/
I think that is just a shocker and won't generate much of a spark. The voltage you need depends on the distance between the electrodes and also on the temperature and pressure. At standard temperature and pressure it takes 75 kilovolts per inch of gap.

[monboy10]

i think that i read that it takes 10,000 volts per 1 cm(not inch) of air
i kind of want to make a new kind fire starter thing besides flint and matches.
and say that if i had 9 volts on that shocker it would give out 3825volts so the sparker wires could be a little over 3mm apart to make a spark