- Also called ballast resistor.a device, often a resistor, that maintains the current in a circuit at a constant value by varying its resistance in order to counteract changes in voltage.
- a device that maintains the current through a fluorescent or mercury lamp at the desired constant value, sometimes also providing the necessary starting voltage and current.
verb (used with object)
Origin of ballast
Word Origin for ballast
"heavy material used to steady a ship," 1520s, from Middle English bar "bare" (see bare; in this case "mere") + last "a load, burden," or borrowed from identical terms in North Sea Germanic and Scandinavian (cf. Old Danish barlast, 14c.). "Mere" because not carried for commercial purposes. Dutch balg-last "ballast," literally "belly-load," is a folk-etymology corruption.