SIST EN IEC 60027-2:2019
(Main)Letter symbols to be used in electrical technology - Part 2: Telecommunications and electronics (IEC 60027-2:2019)
Letter symbols to be used in electrical technology - Part 2: Telecommunications and electronics (IEC 60027-2:2019)
This part of IEC 60027 is applicable to telecommunications and electronics. It gives names
and symbols for quantities and their units.
Formelzeichen für die Elektrotechnik - Teil 2: Telekommunikation und Elektronik (IEC 60027-2:2019)
Symboles littéraux à utiliser en électrotechnique - Partie 2: Télécommunications et électronique (IEC 60027-2:2019)
IEC 60027-2:2019 s'applique aux télécommunications et à l'électronique. Elle donne les noms et symboles des grandeurs et unités.
Črkovni simboli za uporabo v elektrotehniki - 2. del: Telekomunikacije in elektronika (IEC 60027-2:2019)
Ta del standarda IEC 60027 se uporablja za telekomunikacije in elektroniko. Podaja imena in simbole za veličine in njihove enote.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN IEC 60027-2:2019
01-junij-2019
Nadomešča:
SIST EN 60027-2:2008
Črkovni simboli za uporabo v elektrotehniki - 2. del: Telekomunikacije in
elektronika (IEC 60027-2:2019)
Letter symbols to be used in electrical technology - Part 2: Telecommunications and
electronics (IEC 60027-2:2019)
Formelzeichen für die Elektrotechnik - Teil 2: Telekommunikation und Elektronik (IEC
60027-2:2019)
Symboles littéraux à utiliser en électrotechnique - Partie 2: Télécommunications et
électronique (IEC 60027-2:2019)
Ta slovenski standard je istoveten z: EN IEC 60027-2:2019
ICS:
01.075 Simboli za znake Character symbols
31.020 Elektronske komponente na Electronic components in
splošno general
33.020 Telekomunikacije na splošno Telecommunications in
general
SIST EN IEC 60027-2:2019 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN IEC 60027-2:2019
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SIST EN IEC 60027-2:2019
EUROPEAN STANDARD EN IEC 60027-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2019
ICS 01.060, 33.020 Supersedes EN 60027-2:2007
English Version
Letter symbols to be used in electrical technology - Part 2:
Telecommunications and electronics
(IEC 60027-2:2019)
Symboles littéraux à utiliser en électrotechnique - Partie 2: Formelzeichen für die Elektrotechnik - Teil 2:
Télécommunications et électronique Telekommunikation und Elektronik
(IEC 60027-2:2019) (IEC 60027-2:2019)
This European Standard was approved by CENELEC on 2019-02-12. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60027-2:2019 E
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SIST EN IEC 60027-2:2019
EN IEC 60027-2:2019 (E)
European foreword
The text of document 25/635/FDIS, future edition 4 of IEC 60027-2, prepared by IEC/TC 25
"Quantities and units" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC
as EN IEC 60027-2:2019.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2019-11-12
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2022-02-12
document have to be withdrawn
This document supersedes EN 60027-2:2007.
This edition constitutes a technical revision and includes the following significant changes with respect
to the previous edition:
a) former Subclauses 3.8 and 3.9 are cancelled and replaced by EN 80000-13:2008;
b) former Subclause 3.10, now 4.8, is revised in accordance with IEC 60050-192:2015;
c) former Subclause 3.11, now 4.9, is revised in accordance with IEC 60050-561:2014;
d) former Subclause 3.13, now 4.11, is revised in accordance with EN ISO 80000-8:2007,
IEC 60050-801:1994 and IEC 60050-802:2011;
e) technical and editorial corrections have been carried out, mainly in Subclause 4.1.
f) tables are simplified, mainly by deleting useless columns.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Standard IEC 60027-2:2019 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards
indicated:
IEC 60027-3 NOTE Harmonized as EN 60027-3
IEC 60747 (series) NOTE Harmonized in EN 60747 (series)
IEC 61703:2001 NOTE Harmonized as EN 61703:2002 (not modified)
ISO 80000-1:2009 NOTE Harmonized as EN ISO 80000-1:2013 (not modified)
ISO 80000-8:2007 NOTE Harmonized as EN ISO 80000-8:2007 (not modified)
IEC 80000-13:2008 NOTE Harmonized as EN 80000-13:2008 (not modified)
2
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SIST EN IEC 60027-2:2019
EN IEC 60027-2:2019 (E)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60027-1 1992 Letters symbols to be used in electrical
technology - Part 1: General
+ A1 1997 EN 60027-1 2006
+ A2 2005 + A2 2007
3
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SIST EN IEC 60027-2:2019
IEC 60027-2
®
Edition 4.0 2019-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Letter symbols to be used in electrical technology –
Part 2: Telecommunications and electronics
Symboles littéraux à utiliser en électrotechnique –
Partie 2: Télécommunications et électronique
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 01.060; 33.020 ISBN 978-2-8322-6346-4
Warning! Make sure that you obtained this publication from an authorized distributor.
Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
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SIST EN IEC 60027-2:2019
– 2 – IEC 60027-2:2019 © IEC 2019
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Introduction to tables . 5
5 Quantities and units . 6
5.1 General concepts . 6
5.2 Linear time-independent networks under sinusoidal conditions . 20
5.2.1 General . 20
5.2.2 Two-port networks . 20
5.2.3 n-port networks . 28
5.3 Line transmission of signals and telephony . 34
5.3.1 Quantities and units in line transmission . 34
5.3.2 Subscripts for line transmission . 35
5.3.3 Quantities and units in telephony . 36
5.3.4 Subscripts for telephony . 36
5.4 Waveguide propagation . 37
5.4.1 Frequency and wavelength in a waveguide . 37
5.4.2 Characteristic and normalized impedance and admittance in general. 38
5.4.3 Impedance and admittance at a point in a substance . 39
5.4.4 Impedance and admittance at a point in vacuum . 40
5.4.5 Impedance and admittance of a waveguide . 41
5.5 Radiocommunications . 42
5.5.1 General and tropospheric propagation . 42
5.5.2 Ionospheric propagation . 45
5.5.3 Antennas . 46
5.5.4 Radio links. 51
5.6 Optical fibre communication . 53
5.7 Television . 59
5.8 Dependability . 61
5.9 Piezoelectric resonators . 62
5.10 Semiconductor devices . 68
5.11 Electroacoustics . 68
Bibliography . 73
Figure 1 – Conventions concerning signs in electric circuits . 20
Figure 2 – Conventions for n-port linear networks . 28
Figure 3 – Equivalent circuits of a one-port piezoelectric resonator . 62
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SIST EN IEC 60027-2:2019
IEC 60027-2:2019 © IEC 2019 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LETTER SYMBOLS TO BE USED IN ELECTRICAL TECHNOLOGY –
Part 2: Telecommunications and electronics
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC
Publication(s)"). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60027-2 has been prepared by IEC technical committee 25:
Quantities and units.
This fourth edition cancels and replaces the third edition published in 2005. This fourth edition
constitutes a technical revision.
This edition includes the following significant changes with respect to the previous edition:
a) former Subclauses 3.8 and 3.9 are cancelled and replaced by IEC 80000-13:2008;
b) former Subclause 3.10, now 4.8, is revised in accordance with IEC 60050-192:2015;
c) former Subclause 3.11, now 4.9, is revised in accordance with IEC 60050-561:2014;
d) former Subclause 3.13, now 4.11, is revised in accordance with ISO 80000-8:2007,
IEC 60050-801:1994 and IEC 60050-802:2011;
e) technical and editorial corrections have been carried out, mainly in Subclause 4.1.
f) tables are simplified, mainly by deleting useless columns.
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SIST EN IEC 60027-2:2019
– 4 – IEC 60027-2:2019 © IEC 2019
The text of this standard is based on the following documents:
FDIS Report on voting
25/635/FDIS 25/640/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60027 series, published under the general title Letter symbols to
be used in electrical technology, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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SIST EN IEC 60027-2:2019
IEC 60027-2:2019 © IEC 2019 – 5 –
LETTER SYMBOLS TO BE USED IN ELECTRICAL TECHNOLOGY –
Part 2: Telecommunications and electronics
1 Scope
This part of IEC 60027 is applicable to telecommunications and electronics. It gives names
and symbols for quantities and their units.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60027-1:1992, Letter symbols to be used in electrical technology – Part 1: General
IEC 60027-1:1992/AMD1:1997
IEC 60027-1:1992/AMD2:2005
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Introduction to tables
In this part of IEC 60027, complex quantities are in general denoted by underlining their
symbols. However, this does not constitute a compulsory rule in applications (see
IEC 60027-1).
To avoid any ambiguity, some quantity names are followed by a specific use, enclosed in
angle brackets "<…>" after a comma.
When several symbols are indicated for a given quantity, the first is the preferred symbol and
the others are reserve symbols, unless otherwise stated.
When several units are indicated for a given quantity, the first is the coherent SI unit, unless
otherwise stated. For logarithmic ratios, the first mentioned unit is the decibel.
For quantities defined as a logarithm of the ratio of two power quantities or two root-power
quantities (also known as field quantities), the submultiple decibel (dB) of the bel (B) is
generally used, rather than the neper (Np). The bel is not explicitly mentioned in the tables.
See IEC 60027-3 and ISO 80000-1:2009, Annex C.
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SIST EN IEC 60027-2:2019
5 Quantities and units
5.1 General concepts
Quantity Units
Item
Entry
number
number in Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
101 101-12-02 signal S A signal is any physical phenomenon whose presence, absence or variation is The unit depends on the
considered as representing information. In general, a signal is a quantity, one or kind of quantity
s
more parameters of which represent information. constituting the signal
(electric current,
In this document, S and S are used for input and output signals respectively.
1 2
voltage, pressure, etc.).
See IEC 60027-1 for other suitable subscripts.
In cases where the type of signal quantity is known, for example, electric current,
voltage, pressure, etc., use the appropriate symbol.
With respect to capital and lower-case letters, see IEC 60027-1:1992, 2.1.
102 signal power P "s" (lower case, upright) is used as subscript for "signal". watt W
s
P In signal theory, the term "instantaneous power" is by convention used for the
sig
square of the instantaneous value of a signal. This square is proportional to a
physical power if the signal is a root-power quantity (or field quantity)
(see Note 1 to entry of IEC 60050-103:2009, 103-09-05).
In a physical system, a signal power is always a physical power.
103 signal level L decibel dB
S 1 S
L =10 lg dB= ln Np
L S 2 S neper Np
ref ref
s
L
sig
where S and S are two signals of the same kind, S being a reference signal.
ref ref
104 702-07-04 absolute L decibel dB
P 1 P
P
L =10 lg dB= ln Np
power level;
P
P 2 P neper Np
ref ref
power level
where P is a power and P is a reference power.
ref
105 702-07-06 absolute decibel dB
U U
L
U
L =20 lg dB=ln Np
voltage level;
U
U U neper Np
ref ref
voltage level
where U is a voltage and U is a reference voltage.
ref
The synonym "voltage level" may be used only where there is no ambiguity.
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IEC 60027-2:2019 © IEC 2019 – 7 –
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Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
106 702-07-05 relative decibel dB
L L = L −L
r,x r,x P,x P,0
power level
neper Np
where L and L are the absolute power levels (104) at the measuring point
L
P,x P,0
r
and at a reference point, respectively.
107 702-08-03 noise A noise is any variable physical phenomenon, generally a quantity, apparently The unit depends on the
N
not conveying information and which can be superimposed on, or combined with, kind of quantity
n a wanted signal. constituting the noise
(electric current,
Concerning upper and lower-case letters, see IEC 60027-1:1992, 2.1.
S
n voltage, pressure, etc.).
"n" (lower case, upright) is used as subscript for "noise".
s
n
In cases where the type of noise quantity is known, use the appropriate symbol
(for example, I, i for electric current) with n as subscript (e.g. I , i ).
n n
108 103-09-05 power w(f) watt per W/Hz
∞
spectral hertz
P = wf( )d f
∫
density,
0
or noise>
where f is the frequency and P is the total power.
In signal theory, the term "instantaneous power" is by convention used for the
square of the instantaneous value of a signal or noise. This square is
proportional to a physical power if the signal or the noise is a root-power (or field
quantity). See Note 1 to entry of 103-09-05 in IEC 60050-103:2009.
In a physical system, the power spectral density is always a physical power
spectral density.
109 power N The power spectral density (108) is frequency-independent: watt per W/Hz
0
spectral w(f) = N hertz
0
density of
white noise
110 702-08-51 equivalent U Applies to a one-port network. volt V
n
noise
U is an RMS voltage.
voltage n
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Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
111 702-08-52 equivalent Applies to a one-port network. ohm Ω
R
eq
noise
2
resistance; U
n
R
R =
n
eq
4 kT ∆f
ref
noise
resistance
is the equivalent noise voltage (110), k is the Boltzmann constant, T
where U
n ref
is a reference temperature and ∆f is the frequency bandwidth (154) considered.
The synonym "noise resistance" may be used only where there is no ambiguity.
112 702-08-54 spot noise T(f) Applies to a one-port network. kelvin K
temperature f is frequency.
113 702-08-55 mean noise Applies to a one-port network. kelvin K
T
temperature
114 702-08-56 equivalent Applies to a two-port network. kelvin K
T ( f )
eq
spot noise f is frequency.
temperature
115 702-08-58 mean Applies to a two-port network. kelvin K
T
eq
equivalent
The synonym "mean noise temperature" may be used only where there is no
noise
ambiguity.
temperature;
mean noise
temperature
116 702-08-57 spot noise Applies to a two-port network. one 1
Ff()
factor The noise factor is the ratio of the exchangeable power spectral density (108) of
output noise to the power spectral density that would be present at the output if
the only source of noise were input thermal noise at a reference temperature
:
T
ref
Tf()
eq
Ff() 1+
T
ref
where T ( f ) is the equivalent spot noise temperature (114).
eq
For exchangeable power, see IEC 60050-702:1992, 702-07-11.
=
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Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
117 702-08-57 spot noise decibel dB
F ( f ) 1
n
F f = 10 lg Ff dB = ln Ff Np
figure ( ) ( ) ( )
n
neper Np
2
F ()f
where is the spot noise factor (116).
In English, "noise factor" is generally used for the arithmetic expression and
"noise figure" is used for the logarithmic expression. See IEC 60050-702:1992,
702-08-57, Note 2.
In French, "facteur de bruit" is generally used in both cases.
118 702-08-59 mean noise Applies to a two-port network. one 1
F
factor;
T
eq
F 1+
noise factor
T
ref
where T is the mean equivalent noise temperature (115) and T is a reference
eq
ref
temperature.
The synonym "noise factor" may be used only where there is no ambiguity.
119 702-08-59 mean noise decibel dB
F 1
n
FF10 lg dB ln F Np
figure;
n
neper Np
2
noise figure
where F is the mean noise factor (118).
In English, "noise factor" is generally used for the arithmetic expression and
"noise figure" is used for the logarithmic expression. See IEC 60050-702:1992,
702-08-59, Note 2.
In French, "facteur de bruit" is generally used in both cases and the adjective
"logarithmique" is omitted in practice.
The synonym "noise figure" may be used only where there is no ambiguity.
120 702-08-61 signal-to- k Signal power (102) divided by noise power. one 1
SN
noise ratio;
In practice, the symbol S/N is generally used.
SNR
==
=
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Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
121 702-08-61 signal-to- K decibel dB
1
SN
Kk= 10 lg dB = ln k Np
noise
SN SN SN
neper Np
2
logarithmic
ratio
where k is the signal-to-noise ratio (120).
SN
In practice, the term "signal-to-noise ratio" and the symbol S/N are generally
used.
σ
122 103-07-17 growth Example: decibel dB/s
coefficient per
Np/s
σ t
second
ˆ
ut = u e sin ω t
( )
neper
where u(t) is a sinusoidal function of time t, with angular frequency ω and per
second
uˆ
amplitude .
123 103-05-24 damping δ =−σ decibel dB/s
δ
coefficient per
Np/s
where is the growth coefficient (122).
σ
second
neper
per
second
–1
124 103-07-16 complex s second s Special units are only
s =σ + jjω =−+δω
angular to the used when the real and
p
power imaginary parts are
frequency;
where is the angular frequency, is the growth coefficient (122) and δ is
ω σ
of treated separately.
complex
the damping coefficient (123).
minus
frequency
one
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Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
125 131-15-20 transfer H The unit of the quantity
Ss()
2
function H is the quotient of the
Hs() =
T
unit of s (t) by the unit
2
Ss()
1
of s (t).
1
and S , respectively, are the complex representations of the input and
where S
1 2
output signals, respectively, as functions of the complex angular frequency s
(124).
The complex quantities are generally the Laplace transforms of the time-varying
quantities:
Lst()
2
H =
Lst()
1
where Ls (t) and Ls (t) are the Laplace transforms of the signals s (t) and s (t)
1 2 1 2
and t is time.
126 transfer gain The unit is the same as
G()ω
GH(ωω) = (j )
for H.
where H (σω+ j ) is the transfer function (125).
127 transfer The unit is the
A()ω AG()ωω= 1 / ()
attenuation reciprocal of the unit of
H.
G(ω)
where is the transfer gain (126).
128 transfer If the transfer function H (125) is of dimension one (see IEC 60050-112:2010, one 1 Special units are only
Γ
exponent 112-01-13): used when the real and
imaginary parts are
HG(jωω) ( )exp[−=jB(ω)] exp[Γ (ω)]
treated separately.
Γ AB− j (see 129 and 130).
See also image transfer coefficient (IEC 60050-131:2002, 131-15-25).
129 logarithmic A decibel dB
A 20 (lg e) Re ()ΓΓdB Re () Np
transfer
neper Np
attenuation
where Γ is the transfer exponent (128) and e is the base of the natural
logarithm.
In practice, "transfer attenuation" is used.
==
=
=
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Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
130 phase radian rad
B
B(ωω) = Im(ΓH) = − arg (j )
π
change; 1° = rad
°
degree
ϕ 180
where is the transfer function (125) and Γ is the transfer exponent
H (σω+ j )
phase shift
(128).
131 voltage one 1
U
a
1
U
a =
attenuation U
U
2
factor
where U and U are two voltages. Subscripts 1 and 2 can for example designate
1
...
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