IEEE 280-1985 pdf free.IEEE Standard Letter Symbols for Quantities Used in Electrical Science and Electrical Engineering.
IEEE 280 are mainly restricted to the English and Greek alphabets.? The type families that are used for text inmodern book and journal publishing all include italic (sloping) type faces and related roman (upright) type faces.Theformer are used for quantity symbols, and the latter, for unit symbols—the distinctions are discussed more fully in thefollowing paragraphs. (In the context of this standard, the term roman is used simply to mean upright in contrast withsloping and carries no connotation regarding serifs, line widths, or the like.) In situations where roman and italic arenot both available, care shall be taken to avoid confusion between quantities and units. For example, an underline isfrequently used to indicate italic type, and where an underline can be provided, as in manual typewriting, this practiceis often helpful.
Unconventional type faces should generally not be used for letter symbols. Script and Old English faces, for example,are not appropriate for unit symbols. Such special faces have seen limited use for quantity symbols, but good modernpractice avoids them (see 3.3, last paragraph).
Roman type, in general lowercase, is used for unit symbols, except for a very few that use special signs (such as ° fordegree).If, however, the symbol is for a unit whose name is derived from a proper name, uppercase roman type is usedfor the first letter.’ As a further exception to the general rule, the symbol L is used for liter to avoid confusion betweenthe lowercase letter 1 and the numeral 1. Some additional exceptions arise in the special cases where symbols arejoined, as in eV, the symbol for electronvolt, and in mmHg, the symbol for conventional millimeter of mercury, a unitof pressure. The distinction between upper- and lowercase letters should be followed, even if the symbol appears inapplications where the other lettering is in uppercase style. The form of unit symbols is the same for singular andplural, and they are not followed by a period except at the end of a sentence.
In the complete expression for a quantity, a space should be allowed between the numerical value and the unit symbol.For example, write 35 ram, not 35mm, and 2.371 m, not 2.371m. When the quantity is used in an adjectival sense, ahyphen is often used instead of a space between the number and the unit name or between the number and the symbol(except when the first character of the symbol is not a letter, as in °C).IEEE 280 pdf download.