IEEE 280-1985 (R2003) pdf free download.IEEE Standard Letter Symbols For Quantities Used In Electrical Science And Electrical Engineering.
Abstract: IEEE 280-1985 (R2003) provides letter symbols to represent various quantities (but not units) used in electrical science and technology. The standard is compatible with IEC Publication 27, Letter Symbols to be Used in Electrical Technology.
1. Scope
IEEE 280-1985 (R2003) covers letter symbols used to represent physical quantities in the field of electrical science and electrical engineering. These symbols are independent of the units (see ANSI/IEEE Std 2f)-I978 [2j) employed or special values assigned. Also included are selected symbols for mathematics and for physical constants.
2. References
When the following American National Standards referred to in this standard are superseded by a revision approved by the American National Standards Institute, the latest vision shall he used.
[1] ANSI Y 10.17-1961 (R 1973), American National Standard Guide for Selecting Greek Letters Used as Letter Symbols for Engineering Mathematics.
[2] ANSI/IEEE Std 260-1978. IEEE Standard Letter Symbols for Units of Measurement.
[3] ANSI/IEEE Std 268-1982. American National Standard Metric Practice.
3.2 Alphabets and Typography
Letter symbols are mainly restricted to the English and Greek alphabets.5 The type families that are used for text in modern book and journal publishing all include italic (sloping) type faces and related roman (uprighi) type faces. The former are used for quantity symbols, and the latter, for unit symbols—the distinctions are discussed more fully in the following paragraphs. (In the context of this standard, the term roman is used simply to mean upright in contrast with sloping and carries no connotation regarding serifs. line widths, or the like.) In situations where roman and italic are not both available, care shall be taken to avoid confusion between quantities and units. For example, an underline is frequently used to indicate italic type, and where an underline can he provided, as in manual typewriting, this practice is 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. hut good modern practice avoids them (see 3.3, last paragraph).
Symbols for physical quantities, mathematical variables, indices, and general functions6 are printed in italic (sloping) type. IEEE 280-1985 (R2003) pdf download.