Abstract: An apparatus (10) for driving an electro-luminescent device (12), characterized by: a transformer (14) including a ferrite core (72) and a first primary winding (66), a second primary winding (68) and a secondary winding (70) wound onto said core (72) without an air gap; one end of each of the first and second primary windings (66, 68) being connected together; an electrical circuit arranged to drive said one ends of the first and second primary windings (66, 68); a feed back circuit connected between the electrical circuit and the other end of the second primary winding (68) to control operation of said electrical circuit; one end of the secondary winding (70) being connected to said other end of the second primary winding (68); and the other end of the secondary winding (70) being connected to the electro-luminescent device (12).