The instant-start ballasts frequently used with fluorescent tube lamps provide full voltage and current instantly to the lamp cathodes. This creates a thermal shock to the cathodes that will degrade the cathode and may cause the lamp to fail prematurely. As a result, lamps on instant-start ballasts will only withstand about 12,000 to 15,000 on/off cycles before burning out. In contrast, program-start ballasts go through a soft-start sequence that gently starts the lamp without thermal shock. This enables lamps on program-start ballasts to withstand 50,000 to 100,000 on/off cycles before burning out.
In areas where lights are on continuously, or on during normal working hours (typical 12 hours/day), then instant-start is the best option. Instant-start ballasts are less expensive and slightly more efficient than program-start.
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O.C.D. "Orchid Collecting Dysfunction"
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