Abstract: A device is disclosed for converting fluorescent lighting fixtures, having a conventional series-type ballast with at least two lamps, to effect illumination of only one of the two lamps at a time, but automatically effecting illumination of the other lamp upon that one becoming disabled. The device includes an induction coil to increase the starting boost available to one of the two lamps and also has a varistor. The varistor may be connected across a secondary coil of the ballast which is then arranged to idle. With fixtures having two pairs of instant-start lamps, the varistor is instead connected to an electrode of one lamp of each pair. The device preferably has a series circuit comprising the varistor, the inductive coil, a capacitor and a resistor. Preferably four electrical connections, two across the varistor and two across the inductive coil, are provided to connect the device into the circuitry of the ballast and lamps.