It's a way of making the car easier to start.
First, the coil is designed to provide a full spark at 6 volts. (30,000
volts plus)
Second, the main power feed to the coil has a resistor to drop the 12V
from the battery to some lower voltage.
Third, there is a second power feed to the coil from the starter circuit
that give the coil a full 12V for starting.
That way, the coil output is significantly higher during cranking than
it would otherwise be (particularly since the starter is, at the same
time, drawing significant current). A more potent spark when you're
starting helps the car start easier.
Coils that don't use a "dropping resistor" are built to run on 12 volts
all the time.
Chris K.
"Michel R. Gagne" wrote:
>
> Thanks for the info. I thought about that, but figured that since it was
> connected with those cheepo connectors that it wasn't originally there.
>
> Looking through the VB catalog, I noticed that most of the new coils did not
> mention needing a ballast resistor, though one (Mallory chrome one I think)
> did. I hate to be dense, but could someone enlighten me as to what their
> purpose is?
>
> Thanks,
|