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`

`
`I§.EE Std 100-1996
`
`The IEEE Standard Dictionary of
`Eiectrical and Electronics Terms
`
`Sisth Edition
`
`Standards Coordinating Committee 10, Terms and Definitions
`Jane Radatz, Chair
`
`This standard is one of a number of information technology dictionaries being developed by standards
`organizations accredited by the American National Standards Institute. This dictionary was developed
`under the sponsorship of Voluntary standards organizations, using a consensus-based process.
`
`ISBN l-55:13?-B33-I:
`
`90000
`
`I
`
`
`E
`
`
`9 781559 378338
`
`

`
`lntroéuction
`
`Since the first edition in 1941 of the American Standard Definitions of Electrical Terms, the work now
`known as IEEE Std 100, The IEEE Standard Dictionary of Electrical and Electronics Terms, has evolve!
`into the unique compendium of terms that it is today.
`
`The current edition includes all terms defined in approved IEEE standards through December 1996. Terms
`are categorized by their technical subject area. They are also associated with the standards or publications
`in which they currently appear. In some cases, terms from withdrawn standards are included when no
`current source can be found. Earlier editions of IEEE Std 100 included terms from sources other than
`IEEE standards, such as technical journals, books, or conference proceedings. These terms have been
`maintained for the sake of consistency and their sources are listed with the standards in the back of the
`book.
`
`The practice of defining terms varies from standard to standard. Many working groups that write standards
`prefer to work with existing definitions, while others choose to wréte their own. Thus terms may have
`several similar, although not identical, definitions. Definitions have been combined wherever it has been
`possible to do so by making only minor editorial changes. Otherwise, they have been left as wrétten in
`the original standard.
`
`Users of IEEE Std 100 occasionally comment on the surprising omission of a_ particular term commonly
`used in an electrical or electronics field. This occurs because the terms in IEEE Std 100 represent only
`those defined in the existing or past body of IEEE standards. To respond to this, some working groups
`obtain authorization to create a glossary of terms used in their field. All existing, approved standard
`glossaries have been incorporated into this edition of IEEE Std 100, including the most current glossaries
`of terms for computers and power engineering.
`
`IEEE working groups are encouraged to refer to IEEE Std 100 when developing new or revised standards
`to avoid redundancy. They are also encouraged to investigate deficiencies in standard terms and create
`standard glossaries to alleviate them.
`
`The sponsoréng body for this document was Standards Coordinating Committee 10 on Definitions
`(SCC10), which consisted of the following members:
`
`John W. Balde
`Arthur Ballato
`Bruce Barrow
`William Carey
`Frank A. Denbrock
`Jay Forster
`
`Jane Radatz, Chair
`
`Chris Heegard
`John Horch
`J. L. Koepfinger
`Allen H. Meitzler
`Frank D. Myers
`David E. Roberts
`
`F. A. Saal
`Ralph M. Showers
`Edward N. Skomal
`Kenneth L. Swinth
`Raymond S. Turgel
`Edward F. Vance
`
`

`
`When the IEEE Standards Board approved this standard on 10 December 1996, it had the following
`membership.
`
`Ricieard J. Holleman, Vice Chair
`Donald C. Loughry, Chair
`Andrew G. Salem, Secretary
`
`Gilles A. Baril
`Clyde R. Camp
`Joseph A. Cannatelli
`Stephen L. Diamond
`Harold E. Epstein
`Donald C. Fleckenstein
`Jay Forster*
`Donald N. Heirman
`Ben C. Johnson
`
`*Member Emeritus
`
`E. G. “Al” Kiener
`Joseph L. Koepfinger*
`Stephen R. Lambert
`Lawrence V. McCall
`L. Bruce McClung
`Marco W. Migliaro
`Mary Lou Padgett
`John W. Pope
`
`Jose R. Ramos
`Arthur K. Reilly
`Ronald H. Reimer
`Gary S. Robinson
`Ingo Riisch
`John S. Ryan
`Chee Kiow Tan
`Leonard L. Tripp
`Howard L. Wolfman
`
`Also included are the following nonvoting IEEE Standards Board liaisons:
`
`Satish K. Aggarwal
`Alan H. Cookson
`
`Chester C. Taylor
`
`Kim Breitfelder (1995-present), IEEE Std 100 Editor
`Stephen Huffman (1993-1995), IEEE Std 100 Editor
`
`Assistance was provided by the IEEE Standards editorial staff.
`
`How to arse this dictionary
`
`The terms defined in this dictionary are listed in letter-by-letter alphabetical order. Spaces are ignored in
`this style of alphabetization, so cable value will come before cab signal. Descriptive categories associated
`with the term in earlier editions of IEEE Std 100 will follow the term in parentheses. New categories
`appear after the definitions (see Categories, below), followed by the designation of the standard or stan-
`dards that include the definition. If a standard designation is followed by the letter s, it means that edition
`of the standard was superseded by a newer revision and the term was not included in the revision. If a
`designation is followed by the letter w, it means that edition of the standard was withdrawn and not
`replaced by a revision. A bracketed number refers to the non—IEEE standard sources given in the back
`of the book.
`
`Acronyms and abbreviations are no longer listed in a separate section in the dictionary; rather, they are
`incorporated alphabetically with other terms. Each acronym or abbreviation refers to its expanded term,
`where it is defined. Acronyms and abbreviations for which no definition was included in past editions
`have been deleted from this edition of IEEE Std 100.
`
`Abstracts of the current set of approved IEEE standards are provided in the back of the book. It should
`be noted that updated information about IEEE standards can be obtained at any time from the IEEE
`Standards World Wide Web site at http://standards.ieee.org/.
`
`Categories
`
`The category abbreviations that are used in this edition of IEEE Std 100 are defined below. This infor-
`mation is provided to help elucidate the context of the definition. Older terms for which no category could
`be found have had the category “Stdl00” assigned to them. Note that terms from sources other than IEEE
`standards, such as the National Electrical Code® (NEC®) or the National Fire Protection Association,
`may not be from the most recent editions; the reader is cautioned to check the latest editions of all sources
`for the most up-to-date terminology.
`iv
`
`

`
`bubble sort
`
`113
`
`bugduster
`
`breaks the regions into isolated bubbles. free to move along
`the surface and the presence or absence of a bubble represents
`digital information. S_vnon_vm: magnetic bubble memory.
`(C) 610.10-1994
`
`bubble sort An exchange sort in which adjacent pairs of items
`are compared and exchanged.
`if necessary, and all passes
`through the set proceed in the same direction. Synonyms: ex-
`change selection sort; propagation sort; sifting sort. Cantrast:
`cocktail shaker 5011.
`(C) 6105-1990
`Buchmann-Vleyer pattern See." light pattern.
`buck arm A crossarm placed approximately at right angles to
`the line crossarm and used for supporting branch or lateral
`conductors or turning large angles in line conductors. See
`also: tower.
`(PE/T&D)
`[10]
`bucket (1) (A) (data management) An area of storage that may
`contain more than one record and that is referenced as a whole
`by some addressing technique. (B) (data management) In
`hashing, a section of a hash table that can hold all records
`with identical hash values.
`(C) 610.5-1990
`(2) A device designed to be attached to the boom tip of a line
`truck, crane, or aerial lift and used to support workers in an
`elevated working position. It is normally constructed of fi-
`berglass to reduce its physical weight. maintain strength, and
`obtain good dielectric characteristics Syr-.—r0nym.' basket.
`(PE/T&D) 516-1995, 524-1992
`(3) A colloquial reference for an area of storage that may
`contain more than one record and that is referenced as a whole
`by some addressing technique.
`(C) 610.10-1994
`buffalo See: conductor grip; grip, conductor.
`buffer (1) (buffer storage) (supervisory control, data acqui-
`sition, and automatic control) A device in which data are
`stored temporarily, in the course of transmission from one
`point to another; used to compensate for a difference in the
`flow of data, or time of occurrence of events, when transmit-
`ting data from one device to another.
`(PE/SWG/SUB) 999-1992, C37.1-19875, C37.l00-1992
`(2) (buffer storage) (supervisory control, data acquisition,
`and automatic control) An isolating circuit used to prevent
`a driven circuit from influencing a driving circuit.
`(PE/SWG/SUB) C37.1-1987s,C37.100-1992
`(3) (data processing) A storage device used to compensate
`for a difference in rate of flow of information or time of oc-
`currence of events when transmitting information from one
`device to another.
`(C) 162-l963w
`(4) (elevators) A device designed to stop a descending car or
`counterweight beyond its normal limit of travel by storing or
`by absorbing and dissipating the kinetic energy of the car or
`counterweight. See also: elevator.
`(EEC/PE)
`[119]
`(5) (A) (cornputers) A device or storage area used to store
`data temporarily to compensate for differences in rates of data
`flow, time of occurrence of events, or amounts of data that
`can be handled by the devices or processes involved in the
`transfer or use of the data. Synonym.’ input buffer. (B) (com-
`puters) A routine that accomplishes the objectives in defini-
`tion (A).
`(C) (computers) To allocate. schedule, or use
`devices or storage areas as in definition (A). See also: antic-
`ipatory buffering: dynamic buffering; simple buffering.
`(C) 610.12-1990, 610.5-1990
`(6) A device or storage area used to store data temporarily to
`compensate for differences in rates of data flow, time or oc-
`currence of events. or amounts of data that can be handled
`by the devices or processes involved in the transfer or use of
`the data. Synonyms.‘ input buffer:
`input—output area; output
`buffer.
`(C) 610.10—1994
`(7) (relay) See also: relay spring stud.
`buffer amplifier (1) (general) An amplifier in which the reac-
`tion of output-load-impedance variation on the input circuit
`is reduced to a minimum for isolation purposes. See also:
`amplifier; unloading amplifier.
`145-19835, 165-l977w
`(AP/C)
`(2) An amplifier employed in analog computers that produces
`an output signal equal in magnitude to the input signal but
`
`always of one polarity. Note: This isolates a preceding circuit
`from the effects of the following circuit. See also: unloading
`amplifier.
`(C)
`(510.10-1994
`buffered computer A computer that can perfonn input-output
`and process operations simultaneously by using input and out-
`put buffers.
`(C) 610.10-1994
`buffered input Input that is received using buffers.
`(C) 6105-1990
`buffered interconnect (B1) A device that implements an inter-
`segment connection such that the FASTBUS protocol (FBP
`on one segment is not synchronized with that on the other.
`960-1993
`
`buffered write A write transaction that appears to complete
`when the request is queued in the agent or responder. A buf-
`fered-write transaction returns an optimistic (done-corre=::t)
`status before the responders completion status (which could
`report an error) is available.
`(C/MM)
`1212-19913
`buffering The process of using a buffer. See also: dynamic
`buffering.
`(C) 610.10-1994
`buffer memory (sequential events recording systems) The
`memory used to compensate for the difference in rate of flow
`of information or time of occurrence of events when trans-
`mitting information from one device to another. See also‘
`buffer; event; storage.
`(PE)
`[1]
`buffer pool A collection of buffers that can be allocated and
`used as needed.
`(C) 610.5-1990
`buffer prefix An area contained Within a buffer that is used to
`store control information for the buffer.
`(C) 610.10-1994
`buffer register See: data buffer register; input buffer register.
`buffers (buffer salts) Salts or other compounds that reduce the
`changes in the pH of a solution upon the addition of an acid
`or alkali. See also: ion.
`(EEC/PE)
`[119]
`buffer salts See: buffers.
`
`buffer storage (1) An intermediate storage medium between
`data input and active storage.
`(IA)
`[61]
`(2) (data management) A storage device that is used as a
`buffer. Synonym: buffer store.
`(C) 6105-1990
`(3)
`(telecommunications) Memory provided in a digital
`switching system or digital facility interface (DFI) to com-
`pensate for timing drift and frame regiseation differences be-
`tween a DFI and the switching system. Reduces the proba-
`bility of slips caused by environmentally produced phase
`modulation, such as those resulting from diurnal temperature
`variations. The mechanism for absorbing slips in the DH of
`a local digital switch could consist of several single frame
`stores that are alternately written and read. This scheme al-
`lows the two clocks to drift within the limits of the buffer
`storage. In addition, a type of hysteresis should
`provided
`at the DFT whereby a buffer that was involved in a slip is
`protected against an immediate slip in the reverse direction.
`Enough buffering should be used to minimize such occur-
`rences.
`(COM)
`973—1990vv
`(4) (A) A type of storage that is used as temporary storage:
`to compensate for differences in data rate and data flow. See
`also: dynamic buffering. (B) A portion of main storage that
`is assigned to temporary storage as in definition (A).
`(C) 610.10-1994
`
`buffer store See: buffer storage.
`buffing (electroplating) The smoothing of a metal surface by
`means of flexible wheels, to the surface of which fine abrasive
`particles are applied, usually in the form of a plastic com-
`position or paste. See also: electroplating.
`
`[119]
`(EEC/PE)
`bug (1) (telegraphy) A semiautomatic telegraph key in which
`movement of a lever to one side produces a series of correctly
`spaced dots and movement to the other side produces a single
`dash. See also: error; fault.
`(EEC/PE)
`[119]
`(2) In computer hardware, a recurring physical problem that
`prevents a system or system component from working to-
`gether properly.
`(C) 610.10-1994
`bugduster An attachment used on shortwall mining machines
`to remove cuttings (bugdust) from back of the cutter and to
`
`

`
`commutation shrink ring
`
`l 84
`
`t:tJIIlp&l'e&S\l|'B]I
`
`commutating voltage to a pair of commutating branches and
`the cessation of the resulting transient currents. Note: The
`commutation interval is the same as the overlap interval in an
`externally commutated converter in which the commulating
`voltage is supplied by the ac (alternating current) line.
`(IA) 936-19B'r'w
`commutation shrink ring A member that holds the commuta-
`tor-segment assembly together and in place by being shrunk
`on an outer diameter of and insulated from the commutator-
`segment assembly. See rrlso: commutator.
`
`[119]
`(EECEPE)
`commutator (rotating machinery) An assembly of conducting
`members insulated from one another. in the radial-axial plane.
`against which brushes bear. used to enable current to flow
`from one part of the circuit to another by sliding contact.
`(PE)
`
`[9]
`
`commutator bars See: commutator segments.
`commutator bore Diameter of the finished hole in the core that
`accommodates the armature shaft. See also.‘ commutator.
`(EECIPE)
`[119]
`commutator brush track diameter That diameter of the com-
`mutator segment assembly that after finishing on the armature
`is in contact with t.l1e brushes. See also: commutator.
`[119]
`(EECIPE)
`commutator core The complete assembly of all of the retaining
`members of a commutator. See also: commutator.
`[119]
`(EECIPE)
`commutator-core extension That portion of the core that ex-
`tends beyond the commutator segment assembly. See also.-
`commutator.
`(EEC!PE)
`[I I9]
`commutator inspection cover A hinged or otherwise attached
`part that can be moved to provide access to commutator and
`brush rigging for inspection and adjustment. See also: com-
`mutator.
`(EECIPE)
`[119]
`commutator insulating segments (rotating machinery) The
`insulation between commutator segments.
`(PE)
`[9]
`commutator insulating tube (rotating machinery) The insu-
`lation between the underside of the commutator segment as-
`sembly and the core. See also: commutator.
`(PE)
`[9]
`commutator motor meter (seismic qualification of Class IE
`equipment for nuclear Power generating stations) A motor
`type of meter in which the rotor moves as a result of the
`magnetic reaction between two windings, one of which is
`stationary and the other assembled on the rotor and energized
`through a commutator and brushed. See also: electricity
`meter.
`(PE) 344-19755
`commutator not The retaining member that is used in combi-
`nation with a vee ring and threaded shell to clamp the segment
`assembly. See also: commutator.
`(EECIPE)
`[119]
`commutator riser [rotating machinery] A conducting element
`for connecting a commutator segment to a coil. See also:
`commutator.
`(PE)
`[9]
`commutator-segment assembly A cylindrical ring or disc as-
`sembly of commutator segments and insulating segments that
`are bound and ready for installation. Note: The binding used
`may consist of wire. temporary assembly rings, shrink rings.
`or other means. See also: commutator.
`(EECIPE)
`[119]
`commutator segments [commutator bars) Metal current-can
`tying members that are insulated from one another by insult-
`ing segments and that make contact with the brushes. See
`also: commutator.
`(EECIPE)
`[119]
`commutator shell The support on which the component parts
`of the commutator are mounted. Note.‘ The commutator may
`be mounted on the shaft, on a commutator spider. or it may
`be integral with a commutator spider. See ai'.ro.' commutator.
`{EEC.r‘PE)
`[119]
`commutator-shell insulation {rotating machinery} The insu-
`lation between the under (or in the case of a disc commutator.
`the back) side of the commutator assembled segments and the
`commutator shell. See also: commutator.
`(PE)
`[9]
`commutator vee ring The retaining member that, in combina-
`tion withacommutator shell. clamps or binds the commutator
`
`segments together. See also.‘ commutator.
`
`[l 19]
`(EECIPE)
`commutator vee ring insulation (rotating machinery) The in-
`sulation between the V-ring and the commutator segments.
`(PE)
`[91
`commutator vee-ring insulation extension (rotating ma-
`chillery) The portion of the vee-ring insulation that extends
`beyond the commutator segment assembly. See also: com-
`mutator.
`(PE)
`[9]
`compact disc An optical disk that is compact in size. generally
`4 to 5 inches in diameter. See also: CD-ROM storage; laser
`disk.
`(C) 6l0.l{}-I994
`compact disc read-only memory See: CD-ROM storage.
`compact disc storage See: CD-ROM storage.
`compaction (software) In microprograrnmirtg. the process of
`convening a microprogram into a functionally cquivalerlt mi-
`croprogram that is faster or shorter than the original.
`(C) 6lo.l2— I990
`compamling (data transmission) A process in which com-
`pression is followed by expansion. Note: Companding is of-
`ten used for noise reduction. in which case the compression
`is applied before the noise exposure and the expansion after
`the exposure.
`(PE) 270-l964w, 599-l985w
`cornpartdor (data transmission} A combination of a compres-
`sor at one point in a communication path for reducing the
`amplitude range of signals followed by an expander at another
`point for a complementary increase in the amplitude range.
`Note: The purpose of a ccmpandor is to improve the ratio of
`the signal to the interference entering in the path between the
`compressor and expander.
`(PE) 599-l985w
`company-id A 24-bit binary value used to identify a company
`within the context of the CSR Architecture. The company..id
`values are expected to be uniquely assigned to each company.
`(CIMM) 1212-l99ls
`comparative tests (test, measurement, and diagnostic equip-
`ment) Comparative tests compare end item signal or char-
`acteristic values with a specified tolerance band and present
`the operator with a gofno-go readout; a go for signals withirl
`tolerances. and a no»go for signals out of tolerance.
`[2]
`{M11-)
`comparator (1) A circuit for performing amplitude selection
`between either two variables or between a variable and a con-
`stant.
`(C)
`[20]
`(2) (test. measurement. and diagnostic equipment) A de-
`vice capable of comparing a measured value with predeter-
`mined limits to determine if the value is within these limits.
`(MIL)
`E2]
`(3) (analog computer) A circuit, having only two logic out-
`put states, for comparing the relative amplitudes of two ana-
`log variables. or of a variable and a constant. such that the
`logic signal output of the comparator uniquely determines
`which variable is the larger at all times.
`(C)
`J65-l9?7w
`(4) (software) A software tool that compares two computer
`programs. files. or sets of data to identify commonalities or
`differences. Typical objects of comparison are similar ver-
`sions of source code. object code. data base files. or test re-
`sults.
`(C) 6lCl.12~l990
`compare (1) (mathematics of computing) To examine a quan-
`tity for the purpose of determining its relationship to zero.
`(C)
`‘I034-l986w
`(2) {data management) To examine two items to determine
`their relative magnitudes. their relative positions in a given
`sequence, or whether they are identical.
`{C} 6105-1990
`computer A signal element that performs an AND logic func-
`tion.
`(PEISWG) C37.l00-1992
`oompare&swap A data-access operation that conditionally
`stores a next value to a specified data type and returns the
`previous data value. The store occurs when the addressed
`memory value and a second test value are equal. When ac-
`cessing uncacheo data. this data-access operation generates a
`compateswap bus transaction.
`(CIMM)
`1596.5-1993