G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
G05F3/00—Non-retroactive systems for regulating electric variables by using an uncontrolled element, or an uncontrolled combination of elements, such element or such combination having self-regulating properties
G05F3/02—Regulating voltage or current
G05F3/04—Regulating voltage or current wherein the variable is AC
G05F3/06—Regulating voltage or current wherein the variable is AC using combinations of saturated and unsaturated inductive devices, e.g. combined with resonant circuit