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What is the difference between quartz and ceramic arc tubes?
Metal halide (MH) lamp arc tubes are made of either quartz or ceramic (see Figure 1). Ceramic arc tubes allow higher arc tube temperatures, which manufacturers claim results in better efficacy, color rendering, and color stability. In 2003, when this report was originally written, lamps with ceramic arc tubes were available mainly in wattages below 150 watts (W). Mid-wattage ceramic MH lamps were only beginning to make their way onto the market. Only one manufacturer offered a mid-wattage ceramic MH product, which was also a pulse-start technology. (See "What is the difference between probe-start and pulse-start?")
Figure 1. Arc tube construction |
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