IEEE-270-2006.pdf

IEEE Std 270-2006 (Revision of IEEE Std 270-1966) IEEE Standard Definitions for Selected Quantities, Units, and Related Terms, with Special Attention to the International System of Units (SI) I E E E 3 Park Avenue New York, NY 10016-5997, USA 29 September 2006 IEEE Standards Coordinating Committee 14 Sponsored by the Standards Coordinating Committee on Quantities, Units, and Letter Symbols (SCC14) Copyright The Institute of Electrical and Electronics Engineers, Inc. Provided by IHS under license with IEEELicensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 02:46:46 MDTNo reproduction or networking permitted without license from IHS -,-,- Copyright The Institute of Electrical and Electronics Engineers, Inc. Provided by IHS under license with IEEELicensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 02:46:46 MDTNo reproduction or networking permitted without license from IHS -,-,- Recognized as an IEEE Std 270-2006 American National Standard (ANSI) (Revision of IEEE Std 270-1966) IEEE Standard Definitions for Selected Quantities, Units, and Related Terms, with Special Attention to the International System of Units (SI) Sponsor Quantities, Units, and Letter Symbols Committee of the Standards Coordinating Committee 14 (SCC14) Approved 6 September 2006 American National Standards Institute Approved 30 March 2006 IEEE-SA Standards Board Copyright The Institute of Electrical and Electronics Engineers, Inc. Provided by IHS under license with IEEELicensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 02:46:46 MDTNo reproduction or networking permitted without license from IHS -,-,- Abstract: The definitions for physical quantities and units commonly used in applied science and technology, and for related terms that concern systems of measurement, are included in this standard. Particular emphasis is placed on the International System of Units (Le Système International dUnités, SI). Keywords: International System of Units, measurement, metric, quantities, SI, units _ The Institute of Electrical and Electronics Engineers, Inc. 3 Park Avenue, New York, NY 10016-5997, USA Copyright © 2006 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Published 29 September 2006. Printed in the United States of America. IEEE is a registered trademark in the U.S. Patent +1 978 750 8400. Permission to photocopy portions of any individual standard for educational classroom use can also be obtained through the Copyright Clearance Center. Copyright The Institute of Electrical and Electronics Engineers, Inc. Provided by IHS under license with IEEELicensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 02:46:46 MDTNo reproduction or networking permitted without license from IHS -,-,- iv Copyright © 2006 IEEE. All rights reserved. Introduction This standard supersedes IEEE Std 270-1966. Since the 1966 standard was approved, significant changes have occurred in the International System of Units (SI). Corresponding updates have been issued for some of the documents referred to in this standard. Significantly, those updates represent a movement toward greater formalism in dealing with quantities and valuesan area that has become known as the quantity calculus. Those updates also represent a movement toward global consensus, necessary for international harmonization of standards, which is needed for an increasingly global economy. The global community has made great strides toward universally recognized and used units that transcend language groups, fields of study, and industries. The once common use of thousands of units, some arcane and used only in small fields, others more popularly used but varying in definition, has been replaced by a very small set of simple and well-defined units, the SI. Those defined units are based on fundamental physical quantities. The SI is a practical system. The Eighth Edition of the BIPM brochure B1a on the International System of Units states “The definitions of the base units of the SI were adoped in a context that takes no account of relativistic effects. When such account is taken, it is clear that the definitions apply only in a small spatial domain sharing the motion of the standards that realize them.” The SI includes simple rules that provide robust means by which to combine that small set of units to meet nearly every need in commerce, science, engineering, and technology. Necessarily, the parsimonious nature of this system requires exacting compliance with the rules provided for using those unitsa “grammar” that is as tight as its vocabulary is “succinct.” The global movement toward universally recognized and used quantities is paralleling the progress made on units, but it is not as greatly advanced. Nonetheless, great strides have been made and, increasingly, international consensus is consolidating the thousands of variants for quantity names and symbols to a smaller set. This consolidation of system of quantities, too, requires the use of rigid rules of the quantity calculuss “grammar” to ensure universal understanding and usefulness. It is appropriate, therefore, that the IEEE make this standard available to describe quantities commonly used or encountered in its community. Notice to users Errata Errata, if any, for this and all other standards can be accessed at the following URL: http:/ standards.ieee.org/reading/ieee/updates/errata/index.html. Users are encouraged to check this URL for errata periodically. Interpretations Current interpretations can be accessed at the following URL: http:/standards.ieee.org/reading/ieee/interp/ index.html. _ a The numbers in brackets correspond to those of the bibliography in Annex B. This introduction is not part of IEEE Std 270-2006, IEEE Standard Definitions for Selected Quantities, Units, and Related Terms, with Special Attention to the International System of Units (SI). Copyright The Institute of Electrical and Electronics Engineers, Inc. Provided by IHS under license with IEEELicensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 02:46:46 MDTNo reproduction or networking permitted without license from IHS -,-,- v Copyright © 2006 IEEE. All rights reserved. Patents Attention is called to the possibility that implementation of this standard may require use of subject matter covered by patent rights. By publication of this standard, no position is taken with respect to the existence or validity of any patent rights in connection therewith. The IEEE shall not be responsible for identifying patents or patent applications for which a license may be required to implement an IEEE standard or for conducting inquiries into the legal validity or scope of those patents that are brought to its attention. Participants At the time this standard was completed, the Definitions (SCC14.2) Working Group had the following membership: Theodore Wildi, Chair Gordon Aubrecht Bruce B. Barrow James R. Frysinger Barry N. Taylor Ambler Thompson John T. Scott The following members of the balloting committee voted on this standard as individuals. Balloters may have voted for approval, disapproval, or abstention. William Aird Oscar Amrhyn Gordon Aubrecht Bruce B. Barrow Norman Belecki John Benedict William Brenner Dennis Brownridge Keith Chow Roger Daugherty Stanley Ehrlich Jim Elwell Marcel Fortin James R. Frysinger Dudley Galloway Randall Groves Louis A. Herstein Donald W. Hillger Dennis Hoffman Richard Hulett Stan I. Jakuba Tony Jeffree B. P. Leonard O. Kenneth Lewis Jack Loudon Roger Marks G. Michel John Nichols T. W. Olsen Bipin Patel Ronald Petersen Allan D. Pierce Bill Potts Robert J. Schaaf John T. Scott Ralph M. Showers Barry N. Taylor Theodore Wildi Allen J. Zuckerwar When the IEEE-SA Standards Board approved this standard on 30 March 2006, it had the following membership: Steve M. Mills, Chair Richard H. Hulett, Vice Chair Don Wright, Past Chair Judith Gorman, Secretary Mark D. Bowman Dennis B. Brophy William R. Goldbach Arnold M. Greenspan Robert M. Grow Joanna N. Guenin Julian Forster* Mark S. Halpin Kenneth S. Hanus William B. Hopf Joseph L. Koepfinger* David J. Law Daleep C. Mohla T. W. Olsen Glenn Parsons Ronald C. Petersen Tom A. Prevost Greg Ratta Robby Robson Anne-Marie Sahazizian Virginia Sulzberger Malcolm V. Thaden Richard L. Townsend Walter Weigel Howard L. Wolfman *Member Emeritus Copyright The Institute of Electrical and Electronics Engineers, Inc. Provided by IHS under license with IEEELicensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 02:46:46 MDTNo reproduction or networking permitted without license from IHS -,-,- vi Copyright © 2006 IEEE. All rights reserved. Also included are the following nonvoting IEEE-SA Standards Board liaisons: Satish K. Aggarwal, NRC Representative Richard DeBlasio, DOE Representative Alan H. Cookson, NIST Representative Don Messina IEEE Standards Project Editor Copyright The Institute of Electrical and Electronics Engineers, Inc. Provided by IHS under license with IEEELicensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 02:46:46 MDTNo reproduction or networking permitted without license from IHS -,-,- vii Copyright © 2006 IEEE. All rights reserved. Contents 1. Overview.1 1.1 Scope.1 1.2 Purpose1 1.3 Methodology .1 2. Normative references.2 3. Definitions.2 A.2 B .5 C .6 D.8 E12 F15 G.17 H.17 I.19 J.20 K.20 L22 M.24 N.28 O.29 P29 Q.32 R .33 S34 T37 U.38 V.39 W 40 Y.41 Z42 Annex A (informative) Alternative terms in electricity and electromagnetism.43 Annex B (informative) Bibliography.44 Copyright The Institute of Electrical and Electronics Engineers, Inc. Provided by IHS under license with IEEELicensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 02:46:46 MDTNo reproduction or networking permitted without license from IHS -,-,- Copyright The Institute of Electrical and Electronics Engineers, Inc. Provided by IHS under license with IEEELicensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 02:46:46 MDTNo reproduction or networking permitted without license from IHS -,-,- 1 Copyright © 2006 IEEE. All rights reserved. IEEE Standard Definitions for Selected Quantities, Units, and Related Terms, with Special Attention to the International System of Units (SI) 1. Overview This standard is divided into the following three clauses: Clause 1 provides the scope and purpose of this standard and the methodology used in devising it; Clause 2 references IEEE Std 260.1 and IEEE/ASTM SI 10; and Clause 3 provides definitions.1 The definitions represent the bulk of the standards material and the purpose of the revision. Annex A provides information on an alternative approach to the terms used in electricity and magnetism. 1.1 Scope This standard includes definitions for physical quantities and units commonly used in applied science and technology, and related terms that concern systems of measurement. Particular emphasis is placed on the International System of Units (SI). 1.2 Purpose IEEE Std 270-1966 attempted to cover not only quantities and units, but also the much broader area implied in its title, “General (Fundamental and Derived) Electrical and Electronics Terms.” This scope proved to be far too broad, and the standard could not be maintained. The purpose of this revision is to present authoritative definitions of physical quantities and units and other terms relating to measurement systems, with particular emphasis on the vocabulary used in IEEE/ASTM SI 10. 1.3 Methodology In the preparation of this standard, it was sometimes found that a formal definition is understandable only by the relatively few persons who are familiar with a particular branch of physics, mathematics, or other specialized field of knowledge. This standard will be referred to by many individuals who are not experts in a particular field; consequently, the Definitions Working Group (SCC14.2) decided that a simplified definition should occasionally accompany the more formal definition. 1 For information on references, see Clause 2. Copyright The Institute of Electrical and Electronics Engineers, Inc. Provided by IHS under license with IEEELicensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 02:46:46 MDTNo reproduction or networking permitted without license from IHS -,-,- IEEE Std 270-2006 IEEE Standard Definitions for Selected Quantities, Units, and Related Terms, with Special Attention to the SI 2 Copyright © 2006 IEEE. All rights reserved. Definitions are meant to clarify selected terms. Occasionally, terms used in some definitions are defined themselves. In the preparation of this standard, several references were consulted, as listed in the Bibliography (see Annex B). Many definitions in this standard reflect the wording used in these sources. 2. Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments or corrigenda) applies. IEEE Std 260.1, IEEE Standard Letter Symbols for Units of Measurement (SI Units, Customary Inch- Pound Units, and Certain Other Units).2, 3 IEEE/ASTM SI 10, American National Standard for Use of the International System of Units (SI): The Modern Metric System. 3. Definitions For the purposes of this standard, the following terms and definitions apply. The Authoritative Dictionary of IEEE Standards Terms B104 should be referenced for terms not defined in this clause. - A - 3.1 A: Symbol for ampere, the SI unit of current. 3.2 absorbed dose: The mean energy imparted to an element of irradiated matter, for any ionizing radiation, divided by the mass of this element. NOTEThe symbol for this quantity is D, and its SI unit is the gray (Gy).5 3.3 absorbed dose rate: The time rate of change of absorbed dose. NOTEThe symbol for this quantity is dD/dt, and its SI unit is the gray per second (Gy/s). 3.4 acceleration: The time rate of change of velocity, dv/dt. NOTEThe symbol for this quantity is a, and its SI unit is the meter per second squared (m/s2). 3.5 acceleration of free fall; acceleration due to gravity: The acceleration experienced by an object in free fall, i.e., influenced only by the local gravitational field. See: free fall; reference frame. 2 The IEEE standa