If your interested in how this stuff works Chrysler's master tech conference is a great start.

Ignition
http://www.imperialclub.com/Repair/Lit/Master/259/Page03.htm
and how the electronic version works.
(note: the orange box and other later ECUs only have 5 pins and doesn't need the 5 ohm resistor to regulate operating current)
http://www.imperialclub.com/Repair/Lit/Master/292/page04.htm