BALLAST RESISTOR

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BALLAST RESISTOR

A ballast resistor is defined as a resistor inserted into a circuit to minimize current. Ballast resistors also help to avoid over-current faults in a circuit. An “electric ballast” is a more general term used to refer to an electrical device used to maintain a circuit’s stability by limiting the value of current and voltage. Electric ballasts can be resistors, capacitors, inductors, or a combination of these.

Ballast resistors are able to change resistance with the current. If the current flowing through the resistor increases above the threshold value, the resistance increases. The resistance can then correspondingly decrease as the current decreases.

In this way, the ballast resistor tries to maintain a constant current flowing through a circuit.

The ballast resistor is different from the load resistor. As it acts like a variable load connected with the system. But in the case of load resistor, resistance remains constant with different values of current and voltage.

Ballast resistors are no longer widely used. They have been replaced by electronic circuits that fulfill the same function.

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