I couldn't find a positive ground (earth) story I liked online, so I'll make up my own. The few "conventional" ignition systems I've played with had one side of the points connected to the coil, and the other side to ground (through the condenser).
Positive ground would mean that the points switched the positive lead to the coil. Being firmly in the P to N camp, this seems more natural to me. If I were, say, converting a magneto system to a battery, I'd probably hook it up this way.
Last edited by Chu Chu; 8th March 2013 at 02:05.