This standard describes the essential features and operating characteristics of reference ballasts for high-intensity discharge and low-pressure sodium lamps to operate on 60-Hz sinusoidal ballast systems. The items specified are those that have been found necessary to ensure accurate and reproducible results when either lamps or ballasts are being tested. The specific values of rated input voltage and impedance needed for each size of lamp are listed in the appropriate American National Standards for high-intensity-discharge and low pressure sodium lamps@ ANSI C78.1300 series (ANSI C78.40-1992@ Specifications for Mercury Lamps@ ANSI C78.41-2006@ Guidelines for Low- Pressure Sodium Lamps@ ANSI C78.42-2007@ High-Pressure Sodium Lamps@ ANSI C78.43-2007@ Single-Ended Metal Halide Lamps@ and ANSI C78.44-2006@ Double-Ended Metal Halide Lamps). Important patent disclaimer It is possible that some of the elements of this document may be the subject of patent rights. When this document was approved for publication@ ANSLG did not know of any patent applications@ patents pending@ or existing patents. ANSLG shall not be held responsible for identifying any or all such patent rights.