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There are series power supply for different applications. Low-pressure UV lamps may be used for disinfecting purposes, curing nails and dental fillings, or water purification. The type of lamp used in printing applications is usually a medium pressure, linear (straight tubes), mercury vapor arc lamp. Medium pressure UV lamps cure inks and coatings instantly. It is a photochemical, not a heat process. It allows the equipment to run at very high speeds for extended periods.

General use light bulbs have a filament. The electricity causes the filament to glow, producing light. Medium pressure UV lamps do not have a filament. They utilize a high voltage charge to ionize a mercury/gas mixture in the lamp creating a plasma that emits UV light. This system requires a high voltage/amperage power supply (typically a magnetic ballast transformer with a high voltage capacitor bank). The ballast is wired in series with the lamp and performs two functions. Initially, the ballast provides a high voltage charge to ‘strike’ or ‘ionize’ the mercury. Then, once the mercury is ionized, the ballast reduces the voltage and amperage required to keep the mercury ionized and emit a stable stream of UV light.

These lamps generate a specific wavelength to cure the inks or coatings. Currently, most of these lamps operate at 300 to 600 watts per inch with some newer systems using lamps that generate up to 1000 watts per inch. So a 30 inch UV bulb may be capable of an output of 30,000 watts. They also operate at very high temperatures (850 to 950 Celsius or 1550 to 1750 Fahrenheit).