Originally Posted by MikeC4

yep! RPM. the distance between , and the pulse width of, the 5V pulse train will vary of course, with speed of drill, ie RPM. Of course, a gross malfunction of the reading LED's would be obvious at any RPM....Until my Opti craps out...I love the thing...the concept is awesome, being connected directly to end of camshaft, no lag or slop like the old gear driven distributors...

When mine craps out, I shall hate Opti-spark like all of you who have suffered through replacement!!!