I'm completing a project in the lab that requires a spark. As such I've acquired an ignition coil and can use the Lab's standard 12V DC power supply that connects to the 240V AC Mains to power the ignition coil. My issue is grounding the spark plug. I'm assuming that a spark plug doesn't offer much resistance (something about the voltage ionising the air and lowering resistance significantly?) and that even if it does the output voltage would be too much for the 12V supply to ground. What are my options?
I don't have a schematic so I've drawn a small diagram showing my configuration: