Standard 40-watt, F-40, rapid-start, fluorescentslamps were operated with solid-state ballasts followingsthe standard life-testing cycle of 3 hours on ands20 minutes off for more than 20,000 hours at highsfrequency. Lamp operating characteristics (starting voltage, filament voltage, arc current, and current-crest factor) were studied as factors affecting lampslife. Measurements show that fluorescent lamps can attain rated life at high frequency using solid-state ballasts. When lamps are operated in the dimmedsnode, full filament power is required to sustain lampslife. The rate of lamp lumen depreciation is dependentson the lamp loading and not the operating frequency.