Abstract: A power circuit for a fluorescent discharge lamp comprising a converter for producing a DC output. A voltage controlled oscillator is driven by the output from the converter, the oscillator providing a high voltage output for driving the lamp. The frequency of the output increases and decreases with increases and decreases in the powering voltage from the converter. A current detector detects the current passing through the lamp and controls the output voltage of the converter according to that current to increase the the voltage to strike the lamp and then control the voltage to give the required running current.

Abstract: A safety insulated transformer where there are at least three layers of safety approved insulating material between any parts of the wires forming first and second windings. The first winding is wrapped torroidally with a strip of safety approved insulating material, the successive layers of that wrapping overlapping to form at least two of the required layers of safety approved insulating material, and either overlapping to form all three required layers or at least one of the wires having a coating of safety approved insulation. Preferably the ends of the wire of the first winding have end insulation comprising coiled overlapped layers of safety insulation, and a layer of additional safety insulation material of at least two superimposed thicknesses makes a minimum of one and one half turns transversely of the coil of the first winding around the coil in the region or regions where the ends leave the coil.