This is a Flyback Transformer connected to a quick charge capacitor and 2 camera flash circuits
Do not attempt this instructable if you have no prior experience with high voltage, or if you have a dodgy heart.
Step 1: Tools and Materials
You will need:
-A soldering iron
-a capacitor (see picture)
-a Flyback Transformer
-2 Kodak camera flash circuits
-a battery holder
-2 AA batteries
Step 2: Camera Circuits
On this instructable https://www.instructables.com/id/Coilgun-Handgun/, follow step 1 on how to make a mini charger-circuit. Link the outputs in parallel. Then, connect the inputs in series so they will run off 3v. If they don't work, try putting some diodes in and check your connections. Solder the circuits on the battery holder.
NB, having 2 charger circuits is not essential, one will do the job just fine
Step 3: The Flyback
Follow the instructions on this website http://lifters.online.fr/lifters/labhvps/tht.htm on how to find the primary and secondary coils on a Flyback transformer. Or wind your own primary coil. Solder some wires on and your ready for the next step!
Step 4: The Capacitor and Switch
Solder the capacitor on one of the wires of the Flyback, and the switch on the other. Then solder the other end of the capacitor and the other end of the switch together, making a circuit. Tape it all to the side of the Flyback.
Step 5: Last Step!
Finally, solder the 2 outputs of the camera circuits onto the capacitor, in such a way so when the circuits are switched on, the capacitor charges.
Now put the batteries in the battery holder, turn it on and push the switch while the 2 output wires of the Flyback are about 1-2cm apart, and, look! a spark!
This circuit also works with a car ignition coil in place of the flyback.