-ve coil pack pin?

[chris.rawe]

hey all just a newbie question. for you all i'am trying to make a high voltage fly back pulse circuit from the diagrams given by your lovely selves, and was just wondering where you take the -ve from the coil packs, is it actually from the coil pack or is it from edis? i now pin 2 (centre) is the live in. but was wondering which pin (1 or 3) to use fro this application....many thanks

chris