Boy that pic brings back memories from high school when we used the osilliscopes. The points close voltage fluctuations was called the Coil & Condenser oscillactions before electronic ign came out. Of course we were also taught different things to control coil output like the amount of secondary windings and the size and number of the primary windings (primary ohms) which contribute to primary amps along with dwell. Course electronic units can control primary amps and output also by controlling dwell. I like the charts posted in the links and it makes you realize the engineers work hard to build the correct ign systems. When I first got out of high school in 1974 I remember the average coil ohms was about 1 ohm on the primary and about 10,000 on the secondary as it was a general rule of thumb I used on point systems. I can see in the charts on the links how much its has changed with electronic and MSD units. I also remember when Mopar went to coil packs and then the coil secondary windings had to go out the coil wire and to ground to fire two plugs as most coils before had the secondary windings tied to the coil wire and the primary winding when it fired just one plug and not two at one time like the coil packs do. That link is a good read. Thanks for posting it. Ron