Abstract: An ornamental lamp which includes a light transmitting envelope containing a fluid such as an inert gas or air and at least one electrode disposed within or without said envelope and applying high voltage at a high frequency to said electrode to ionize the fluid to produce ornamental displays and varying the characteristics of the displays by changing the magnitude of the voltage, the frequency and wave form through modulation and a power supply for operating said lamp utilizing a transformer having a high voltage secondary and two low voltage primaries with said primaries being connected to said amplifier to produce a positive feedback signal to cause oscillation thereof and filter means for effecting modulation of the feedback signal.