Abstract: A method and apparatus for causing a strobe-type lamp, i.e. gas discharge lamp, to produce readily discernible warning flashes. In a first embodiment, the light output of a strobe-lamp is partially absorbed by a fluorescent material and released shortly after absorption to produce a visible flash of lesser intensity but greater duration than that actually produced by the lamp. In a second embodiment, the strobe lamp is caused to flash a multiplicity of times at a rate sufficient to give the visible impression of a single continuous flash of long duration. A circuit for energizing the strobe lamp consumes power only while the strobe lamp is flashing, and remains deactuated when the lamp is not energized.