Ballast resistor - is this a must ?

[mr0077]

Before electronic ignitions, during starting, the voltage available to the coil dropped to about 9 volts. To get a full spark, the coil was designed to operate at the current flowing during 9 volts, but after the engine started the voltage would return to 12+ volts and the current through the coil and points would increase. The ballast resistor was put in the circuit so that during starting the resistor was bypassed and coil would see 9 volts (and its related amps), then when the engine was running, the resistor would drop the 12+ volts back to 9 volts, and the coil was seeing the voltage and current for which it was designed. Because the coil was designed for 9 volts (and its related current), the points were too. If you take the resistor out (on an old system), the coil and points will see 9 volts and an appropriate amperage during starting and 12+ and a higher current when running. The excess current driven by the higher voltage will burn the points, and will probably cause eventual failure of the coil too.

On new (electronic) systems, the resistor is usually not necessary or actually must be deleted. Some new systems use points for a trigger, but they carry a very small current, which is the part that burns the points, so the resistor isn't needed.

Did I say that right?