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i dont agree with the post that says a ballast resistor is supposed to change resistance with temperature. .




You might not agree but you would be wrong. The fact that a BALLAST changes resistance is the entire reason it's called a ballast. Otherwise it would simply be a resistor. MOST resistors used in electronics are intended NOT to change resistance, even though they do somewhat, but they are NOT "BALLAST" resistors.

In the case of Chrysler, this is exactly what they are. Somewhere in the pile of old books around here, I've got documentation to back this up. I am NOT gonna spend time looking for it


okay. youre right. i retract my previous comment. I have just never heard that about a ballast resistor before you said it and my thinking was that a ballast resistor was simply a resistor.

i googled it and yes. youre right. a ballast resistor changes resistance based on the current flowing through it.

thanks for teaching me something i never knew

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Home > Library > Science > Sci-Tech Encyclopedia

A resistor that has the property of increasing in resistance as current flowing through it increases, and decreasing in resistance as current decreases. Therefore the ballast resistor tends to maintain a constant current flowing through it, despite variations in applied voltage or changes in the rest of the circuit. See also Resistor.

The ballast action is obtained by using resistive material that increases in resistance as temperature increases. Any increase in current then causes an increase in temperature, which results in an increase in resistance and reduces the current. Ballast resistors may be wire-wound resistors. Other types, also called ballast tubes, are usually mounted in an evacuated envelope to reduce heat radiation.

Ballast resistors have been used to compensate for variations in line voltage, as in some automotive ignition systems, or to compensate for negative volt-ampere characteristics of other devices, such as fluorescent lamps and other vapor lamps. See also Fluorescent lamp; Vapor lamp; Voltage regulator.