Why a Resistor?

[JayChicago]

Originally Posted by rotorwrench

When ...Henry's insistence on using the distributor mounted coils required coil designs that were outside the normal.....The little coils only needed 4 amps or so to do a good reliable job so Ford used a 0.8 OHM ballast to control the current..

Thank you. Finaly an explanation that makes sense to me. Using a little coil required use of an external resistor. It's that simple!