Abstract: An apparatus and method for thermally controlling a light fixture contemplate the use of a housing for holding a high-wattage, heat-producing lamp, with the housing having an opening through which light emanates from the lamp. Two lenses are provided, and mounting means support the lenses in spaced layered relation so as to form a thermal barrier that at least partially encloses the opening of the housing whereby the lens furthest from the heat-producing lamp is maintained cooler than the lens closest to the lamp.

Abstract: A bi-level ballast network is disclosed for operating an HID lamp at either a low power or standby level and at a high power or full light level. The network includes an unswitched capacitor connected to the transformer ballast coil and a switched capacitor connected to a solid state relay (SSR) circuit, the electronic components providing the switching therein being back-to-back SCR's. When the SSR is operated the contacts connected to the switched capacitor open or close at the next subsequent zero crossing of the applied ac source voltage. This changes the capacitance of the network to increase the power to the lamp or decrease the power thereto depending on the operating condition prior to the SSR being operated. Current, voltage and dvdt protection devices are also provided.