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Fluorescent electronic ballasts have other advantages over electromagnetic types:
•	They operate the lamp at a high frequency (25 kHz), which increases lamp efficacy by approximately 10%. This means they are more energy efficient.
•	They run cooler.
•	Flicker is virtually eliminated.
•	The newer generations are more compact.
•	One need not strain to lift them.

As we said, HID ballasts are almost always the electromagnetic type. Why? Because HID lamps for general lighting applications span a wattage range of 35W to 1500W and for anything over about 150W, the cost of electronic ballasts increases at about the same rate as sports stars’ salaries.

HID ballasts come in a dizzying array of sizes, shapes, types, wattages, and configurations. This is necessary in order to handle the different types of HID lamps you have just learned about, the different applications (street lighting, parking garages, warehouses, factories, high interior ceilings, building facades, sports stadiums, etc.), the different types of fixtures (outdoor floodlights, poles, bollards, recessed downlights, high-bay, low-bay, San Francisco Bay, etc.),…well, you get the point.

Electronic HID ballasts do have advantages over electromagnetic types, but not to the same extent as the fluorescents. Here are the advantages:
•	HID electromagnetic ballasts are really heavy. Reduced size and weight of electronic types allows HID to be used in track lighting without the need to weld the track to a steel I-beam.
•	They exhibit improved power regulation to the lamp – provides improved color consistency and reduces the lamp’s susceptibility to power fluctuations.

One inescapable aspect of all ballasts is that they consume some energy. Therefore, the total power used by a ballasted lighting system must include both the lamp power and the ballast losses. For fluorescent systems, the ballast losses (for either electromagnetic or electronic) are about 10% of the total lamp power; so one must add 10% to the lamp power to determine the total system power consumption. For HID systems, the factor is about 12% - 15% for the ballast. Remember, these are typical, not absolute values. Always check manufacturers’ catalogs for specifics about the particular ballast you have in mind.