Dual Ballast Resistor

The dual ballast resistor serves to maintain constant primary current with various engine speeds. The normal side (1.25 ohms) of dual ballast resistor is a compensating resistance in ignition primary circuit. During low speed operation current is maintained in this side of ballast resistor for a longer period of time, causing it to heat up, and resistance to increase. As engine speed increases the amount of time current is maintained in this side of resistor is shortened, causing it to cool off and resistance to decrease. This action raises voltage in primary circuit. This side of dual ballast resistor is by-passed during engine cranking. The auxiliary side of resistor (5.0 ohms) maintains a constant voltage to ECU.