[Double Venom]

Jerry,
You took the words out of my mouth---kind of goes back to the Ol' Magneto days!

STEPHEN, Leading edge is the same as "Phasing- Start and finish!- As I understand it.
Phase starts at the exact point the light (or circuit) is complete/turns ON. End of the phase is when it will turn OFF. Then there is a phase (which you shouldn't have to give credence to.) that is between the 'points'. After that the "Phasing" will start all over again to fire the next plug. This is my 2-cents take of it all!
DV