Fun with car ignition coils? Or use : )

[Hayato]

Jacob ladder are relly nice.

I used to use a neon transformer to do that.

 

[Someone Electro]

Yes arcs from ignition coil are very loud because the coil operates in the audio range. Its the worst choice for audio modulation because of that.

As for a jacobs lader you will need to run the ignition coil well out of its rated specs (And they can be driven many times harder than what they are in the car) Thing is to make a jacobs lader work you need a very hot and constant arc to make the air convection push it up.

To get the most out of a ignition coil you can run it as a transformer, however for that 12V is much too low. In the car the inductive kickback creates well above 100V on the primary and thats why they can develop such high voltages.I used a IGBT Hbridge to drive one and it was powerd by 300V to drive it at its resonant freqency (about 16Khz). It created big while flaming arcs and made little discharges in to free air. But i stuck a rubber hose over the neck the HV comes out to keep it from arcing over to the terminals. After a lot of operation at these ridiculusly high powers the coil arced over interany and fried it self.

For some serius high powers you can wind your own HV transformer, they can be incredibly reliable if done properly.

 

[unclejed613]

we used to make them out of ignition transformers from heating oil furnaces. the transformers were usually in the shape of an 8 inch cube with the terminals about 3 inches apart on one face of the cube. the terminals were threaded bolts with nuts on them. these transformers put out 10kVrms @ 100mA. they were heavy enough that you could use them as the base for a very large (6 ft tall) jacob's ladder without it wanting to tip over. we would fashion the electrodes from 12ga bare copper wire and secure it at both ends with wooden or plastic rods (when the arc is burning, the magnetic and electrostatic effects between the wires tend to pull them together). it was tricky getting the strike area at the bottom to the correct distance so that the jacob's ladder would start on it's own and still release the arc up the wires. once it was set up properly set up, it would happily BzzzzzzztBzzzzzztBzzzzzt away unattended. depending on the humidity, the arc would climb all the way to the top with a spark length well in excess of 3 or 4 inches. if you could catch a spark on it's way up, you could light a cigarette with it. the electrodes oxidize rapidly, so you need to clean them periodically with sandpaper. WARNING!!! CLEAN AND ADJUST ELECTRODES ONLY WHILE THE UNIT IS UNPLUGGED, DO NOT RELY ON POWER SWITCHES. 10Kv@100Ma IS A POTENTIALLY LETHAL COMBINATION!!!!.... also remember that the electrodes get HOT, and should be allowed to cool before adjusting or cleaning them. large neon sign transformers can be used as well, but are usually only 50mA devices, so the results will not be as spectacular. the ignition transformers are rated for somewhat continuous duty, and will run relatively cool for 20 or so minutes at a time. with the electrodes and their connections, try to avoid sharp points at the ends of the wires or any solder joints you make. the sharp points can bleed off current in the form of corona discharge. this is one time where large blobs of solder on a connection is actually desirable. the blobs should be smooth with no points or inclusions (half formed bubbles)