CLC/SR 25 - Quantities and units, and their letter symbols

IEC 80000-6:2022 gives names, symbols, and definitions for quantities and units of electromagnetism. Where appropriate, conversion factors are also given. International Standard IEC 80000-6 has been prepared by IEC technical committee 25: Quantities and units, and their letter symbols in close cooperation with ISO/TC 12, Quantities and units. This standard is based on classical electromagnetism, i.e. mainly Maxwell’s equations. No reference is made to quantum field theories. IEC 80000-6:2022 cancels and replaces the first edition published in 2008. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: 1) With the new definitions in SI, some previously exact values for quantities now must be determined experimentally while other quantities are given as exact values; 2) Item 6-2.2, elementary charge added; 3) Item 6-11.4, induced voltage, added; 4) Index of entries added; 5) Editorial alignment to other parts of the IEC and ISO 80000 series.

Defines rules for the use and writing of letter symbols for telecommunications and electronics.

IEC 60375:2018 specifies the rules for signs and reference directions and reference polarities for electric currents and voltages in electric networks.

IEC 60027-7:2010 is applicable to generation, transmission, and distribution of electric energy. It gives names and letter symbols for quantities and units. In addition, rules for multiple subscripts and their succession are given. It is an addition to IEC 60027-1. Therefore letter symbols already given in IEC 60027-1 are repeated only if they have a special meaning in the field of power generation, transmission, and distribution or if they are used in this field with special subscripts.

IEC 62428:2008 deals with transformations from original quantities into modal quantities for the widely used three-phase a.c. systems in the field of electric power engineering. The examination of operating conditions and transient phenomena in three-phase a.c. systems becomes more difficult by the resistive, inductive or capacitive coupling between the phase elements and line conductors. Calculation and description of these phenomena in three-phase a.c. systems are easier if the quantities of the coupled phase elements and line conductors are transformed into modal quantities. The calculation becomes very easy if the transformation leads to decoupled modal systems. The original impedance and admittance matrices are transformed to modal impedance and admittance matrices. In the case of decoupling of the modal quantities, the modal impedance and admittance matrices become diagonal matrices.

In IEC 80000-13:2008, names, symbols and definitions for quantities and units used in information science and technology are given. Where appropriate, conversion factors are also given. International Standard IEC 80000-13 has been prepared by IEC technical committee 25: Quantities and units, and their letter symbols in co-operation with ISO/TC 12. This standard cancels and replaces subclauses 3.8 and 3.9 of IEC 60027-2:2005. The only significant change is the addition of explicit definitions for some quantities.

In IEC 80000-6:2008, names, symbols, and definitions for quantities and units of electromagnetism are given. Where appropriate, conversion factors are also given. International Standard IEC 80000-6 has been prepared by IEC technical committee 25: Quantities and units, and their letter symbols in close cooperation with ISO/TC 12, Quantities, units, symbols, conversion factors. This first edition of IEC 80000-6 cancels and replaces the second edition of ISO 31-5, published in 1992, and its amendment 1 (1998).

This part of IEC 60027 is applicable to control technology. It gives names and symbols for quantities, signals and functions, and their units.

This part of IEC 60027 is applicable to rotating electric machines. It gives names and symbols for quantities and units.

Applies to logarithmic quantities and units. Quantities that can be expressed as the logarithm of a dimensionless quantity, such as the ratio of two physical quantities of the same kind, can be regarded and treated in different ways. In many cases, differences do not affect practical treatment.

The contents of the corrigendum of April 1993 have been included in this copy.

Defines rules for the use and writing of letter symbols for telecommunications and electronics.

In IEC 80000-14:2008, names, symbols, and definitions for quantities and units of telebiometrics related to human physiology are given. This part of IEC 80000 encompasses quantities and units for physiological, biological or behavioural characteristics that might provide input or output to telebiometric identification or verification systems (recognition systems), including any known detection or safety thresholds. It also includes quantities and units concerned with effects on a human being caused by the use of a telebiometric device. International Standard IEC 80000-14 has been prepared by IEC technical committee 25: Quantities and units, and their letter symbols in co-operation with ISO/TC 12.

Applies to logarithmic quantities and units. Quantities that can be expressed as the logarithm of a dimensionless quantity, such as the ratio of two physical quantities of the same kind, can be regarded and treated in different ways. In many cases, differences do not affect practical treatment.

Gives letter symbols for quantities and units used in electrical technology, and rules for their use and combination. Also specifies alphabets, subscripts, singularity functions, distributions and letter styles.

Lays down rules for signs and reference directions and reference polarities for electric currents and voltages in electric networks, as well as for the corresponding quantities in magnetic circuits.

Defines rules for the use and writing of symbols for general quantities, symbols for quantities concerning two-port networks, symbols for line transmissions of signals (including cables), symbols for radio wave propagation, symbols for quantities concerning waveguide propagation, symbols for aerials (antennas), symbols for electro-acoustics and symbols for equivalent circuits of piezo-electric crystals.

Applies to logarithmic quantities and units. Quantities that can be expressed as the logarithm of a dimensionless quantity, such as the ratio of two physical quantities of the same kind, can be regarded and treated in different ways. In many cases, differences do not affect practical treatment.

Contains letter symbols for quantities related to rotating electrical machines. Concerns dimensional characteristics as well as performance under different operating conditions.