SIST EN IEC 60477-2:2022
(Main)Laboratory resistors - Part 2: Laboratory AC resistors (IEC 60477-2:2022)
Laboratory resistors - Part 2: Laboratory AC resistors (IEC 60477-2:2022)
This part of IEC 60477 applies to resistors intended as laboratory AC resistors for use over a range of frequencies from DC up to a stated frequency which is not in excess of 1 MHz. Such resistors are hereinafter referred to as "AC resistors".
In addition to satisfying the requirements of IEC 60477, resistors satisfying the requirements of this standard are designed to have a small variation of resistance and a small phase displacement over the stated frequency range.
Because of the uncertainties in AC properties which can result from stray inductances, stray capacitances, eddy currents, dielectric absorption effects and skin effect, the AC resistors to which this standard applies are classified according to their construction (see Annex D), as follows:
a) Two-terminal resistor which each of one terminal both for current and potential;
b) Three-terminal resistor which has one more shield terminal (also could be called as guard terminal) connected to the electric screen than the two-terminal resistor to reduce the stray capacitances effect;
c) Four-terminal resistor which has independent current terminals and potential terminals to reduce the stray inductances and contact resistances;
d) Five-terminal resistor which has one more shield terminal than the four-terminal resistor;
e) Four-terminal coaxial resistor which has two terminal-pairs with the outer shield conductors working as the low terminal of current or potential;
f) Two-terminal-pair resistor which has two terminal-pairs with the outer shield conductors working as the return path for the signal current (not grounded);
g) Four-terminal-pair resistor which has four terminal-pairs with the outer shield conductors working as the return path for the signal current (not grounded) to eliminate the effect of mutual coupling between the current and potential leads.
Labor-Widerstände - Teil 2: Labor-Wechselstromwiderstände (IEC 60477-2:2022)
Résistances de laboratoire - Partie 2: Résistances de laboratoire à courant alternatif (IEC 60477-2:2022)
L'IEC 60477-2:2022 s’applique aux résistances destinées à être utilisées comme résistances de laboratoire à courant alternatif dans un domaine de fréquences allant du courant continu jusqu’à une fréquence déclarée ne dépassant pas 1 MHz. Ces résistances sont, par la suite, désignées par l’expression "résistances à courant alternatif".
Les résistances qui, non seulement, satisfont aux exigences de l’IEC 60477-1, mais qui satisfont aussi aux exigences du présent document sont conçues de façon à avoir une variation de résistance faible et un déphasage faible dans le domaine de fréquences déclaré.
L'IEC 60477-2:2022 annule et remplace la première édition parue en 1979 et l’Amendement 1:1997. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l’édition précédente:
a) extension du domaine de fréquences des résistances à courant alternatif à 1 MHz;
b) mise à jour des termes et définitions conformément à la série IEC 60050;
c) ajout de la définition de la différence entre le courant alternatif et le courant continu pour une résistance à courant alternatif;
d) ajout de la classification des résistances en fonction de la résistance en courant alternatif ou à l’indice de différence entre le courant alternatif et le courant continu;
e) mise à jour de la classification en fonction de la construction des résistances à courant alternatif;
f) mise à jour des symboles de sécurité et des exigences conformément à l’IEC 60477-1;
g) ajout des circuits équivalents à trois éléments d’une résistance à courant alternatif à l’Annexe C;
h) ajout de l’annexe relative aux constructions des résistances à courant alternatif.
Laboratorijski upori - 2. del: Laboratorijski upori za izmenični tok (IEC 60477-2:2022)
Ta del standarda IEC 60477 se uporablja za upore, ki so predvideni kot laboratorijski upori za izmenični tok za uporabo v frekvenčnem območju od enosmernega toka do navedene frekvence, ki ne presega 1 MHz. Za take upore se v nadaljnjem besedilu uporablja izraz »upori za izmenični tok«.
Poleg izpolnjevanja zahtev iz standarda IEC 60477 so upori, ki ustrezajo zahtevam iz tega standarda, zasnovani tako, da imajo v določenem frekvenčnem območju majhno spremembo upornosti in majhen fazni pogrešek.
Zaradi negotovosti pri lastnostih izmeničnega toka, ki so lahko posledica blodeče induktivnosti, blodeče kapacitivnosti, vrtinčnih tokov, učinkov dielektrične absorpcije in segrevanja površine, so upori za izmenični tok iz tega standarda razvrščeni glede na njihovo izvedbo (glej dodatek D), kot sledi:
a) upor z dvema priključkoma, od katerih vsak vključuje po en priključek za tok in potencial;
b) upor s tremi priključki, pri katerem je z električnim zaslonom povezan en zaščitni priključek več kot pri uporu z dvema priključkoma, s čimer se zmanjša učinek blodeče kapacitivnosti;
c) upor s štirimi priključki, ki vključuje neodvisne priključke za tok in potencial, s čimer se zmanjšata blodeča induktivnost in kontaktna upornost;
d) upor s petimi priključki, ki vključuje en zaščitni priključek več kot upor s štirimi priključki;
e) koaksialni upor s štirimi priključki, ki vključuje dva para priključkov z zunanjimi zaščitnimi vodniki, ki delujejo kot priključek za tok oziroma potencial;
f) upor z dvema paroma priključkov, ki vključuje dva para priključkov z zunanjimi zaščitnimi vodniki, ki delujejo kot povratna pot za signalni tok (neozemljen);
g) upor s štirimi pari priključkov, ki vključuje štiri pare priključkov z zunanjimi zaščitnimi vodniki, ki delujejo kot povratna pot za signalni tok (neozemljen), da se odpravi učinek medsebojnega spajanja vodov toka in potenciala.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN IEC 60477-2:2022
01-oktober-2022
Nadomešča:
SIST EN 60477-2:2000
SIST EN 60477-2:2000/A1:2000
Laboratorijski upori - 2. del: Laboratorijski upori za izmenični tok (IEC 60477-
2:2022)
Laboratory resistors - Part 2: Laboratory AC resistors (IEC 60477-2:2022)
Labor-Widerstände - Teil 2: Labor-Wechselstromwiderstände (IEC 60477-2:2022)
Résistances de laboratoire - Partie 2: Résistances de laboratoire à courant alternatif
(IEC 60477-2:2022)
Ta slovenski standard je istoveten z: EN IEC 60477-2:2022
ICS:
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
SIST EN IEC 60477-2:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN IEC 60477-2:2022
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SIST EN IEC 60477-2:2022
EUROPEAN STANDARD EN IEC 60477-2
NORME EUROPÉENNE
EUROPÄISCHE NORM May 2022
ICS 17.220.20; 31.040.01 Supersedes EN 60477-2:1997 + A1:1997
English Version
Laboratory resistors - Part 2: Laboratory AC resistors
(IEC 60477-2:2022)
Résistances de laboratoire - Partie 2: Résistances de Labor-Widerstände - Teil 2: Labor-
laboratoire à courant alternatif Wechselstromwiderstände
(IEC 60477-2:2022) (IEC 60477-2:2022)
This European Standard was approved by CENELEC on 2022-05-04. 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, 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
© 2022 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60477-2:2022 E
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SIST EN IEC 60477-2:2022
EN IEC 60477-2:2022 (E)
European foreword
The text of document 85/822/FDIS, future edition 2 of IEC 60477-2, prepared by IEC/TC 85
"Measuring equipment for electrical and electromagnetic quantities" was submitted to the IEC-
CENELEC parallel vote and approved by CENELEC as EN IEC 60477-2:2022.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2023-02-04
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2025-05-04
document have to be withdrawn
This document supersedes EN 60477-2:1997 and all of its amendments and corrigenda (if any).
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.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 60477-2:2022 was approved by CENELEC as a European
Standard without any modification.
2
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EN IEC 60477-2:2022 (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 60477-1 - Laboratory resistors - Part 1: Laboratory - -
DC resistors
3
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SIST EN IEC 60477-2:2022
IEC 60477-2
®
Edition 2.0 2022-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Laboratory resistors –
Part 2: Laboratory AC resistors
Résistances de laboratoire –
Partie 2: Résistances de laboratoire à courant alternatif
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220.20; 31.040.01 ISBN 978-2-8322-1092-7
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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– 2 – IEC 60477-2:2022 © IEC 2022
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Resistor characterization and construction. 8
4.1 Resistor characterization . 8
4.2 Resistor construction . 9
5 General requirements . 9
5.1 DC resistance, AC resistance and time constant . 9
5.2 Multiple resistors . 10
5.3 Multi-dial resistors. 10
5.4 Connecting leads . 10
5.5 Conditions for the determination of DC and AC characteristics . 11
6 Permissible variations . 11
7 Further electrical and mechanical requirements . 12
8 Information, markings and symbols . 12
8.1 Information . 12
8.2 Markings and symbols . 12
Annex A (informative) Examples of markings . 14
A.1 Example of marking for a single AC resistor . 14
A.2 Example of marking for a five-dial AC resistor . 14
Annex B (informative) General considerations regarding laboratory AC resistors . 16
Annex C (informative) Equivalent circuits of an AC resistor . 18
C.1 General . 18
C.1.1 Two-element equivalent circuit of an AC resistor . 18
C.1.2 Three-element equivalent circuits . 20
C.2 Guard terminal . 23
Annex D (informative) Construction of AC resistors . 24
D.1 Construction and electrical definition of the impedance . 24
D.2 Two-terminal resistor . 24
D.3 Three-terminal resistor . 24
D.4 Four-terminal resistor . 25
D.5 Five-terminal resistor . 25
D.6 Four-terminal coaxial resistor . 26
D.7 Two-terminal-pair resistor . 26
D.8 Four-terminal-pair resistor . 27
Figure A.1 – Example of marking for a single AC resistor . 14
Figure A.2 – Example of marking for a five-dial resistor . 14
Figure C.1 – The three-element equivalent circuit of an AC resistor (Category A) . 20
Figure C.2 – The three-element equivalent circuit of an AC resistor (Category C) . 22
Figure D.1 – Two-terminal resistor . 24
Figure D.2 – Three-terminal resistor . 25
Figure D.3 – Four-terminal resistor . 25
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Figure D.4 – Five-terminal resistor . 26
Figure D.5 – Four-terminal coaxial resistor . 26
Figure D.6 – Two-terminal-pair resistor . 27
Figure D.7 – Four-terminal-pair resistor . 27
Table 1 – Limits of the AC resistance relative uncertainty . 9
Table 2 – Limits of the AC/DC difference . 10
Table 3 – Upper limit of the nominal range of use for frequency . 11
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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LABORATORY RESISTORS –
Part 2: Laboratory AC resistors
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.
IEC 60477-2 has been prepared by IEC technical committee 85: Measuring equipment for
electrical and electromagnetic quantities. It is an International Standard.
This second edition cancels and replaces the first edition published in 1979, and
Amendment 1:1997. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) extended the AC resistor frequency range to 1 MHz;
b) updated the terms and definitions according to IEC 60050 series;
c) added the definition of AC/DC difference of an AC resistor;
d) added the resistor classification according to the AC resistance or AC/DC difference index;
e) updated the classification according to the AC resistor construction;
f) updated the safety symbols and requirements according to IEC 60477-1;
g) added the three-element equivalent circuits of an AC resistor in Annex C;
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IEC 60477-2:2022 © IEC 2022 – 5 –
h) added the annex on constructions of AC resistors.
The text of this International Standard is based on the following documents:
Draft Report on voting
85/822/FDIS 85/825/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
A list of all parts in the IEC 60477 series, published under the general title Laboratory resistors,
can be found on the IEC website.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under 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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LABORATORY RESISTORS –
Part 2: Laboratory AC resistors
1 Scope
This part of IEC 60477 applies to resistors intended as laboratory AC resistors for use over a
range of frequencies from DC up to a stated frequency which is not in excess of 1 MHz. Such
resistors are hereinafter referred to as "AC resistors".
In addition to satisfying the requirements of IEC 60477-1, resistors satisfying the requirements
of this document are designed to have a small variation of resistance and a small phase
displacement over the stated frequency range.
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 60477-1, Laboratory resistors – Part 1: Laboratory DC resistors
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• ISO Online browsing platform: available at http://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/
3.1
equivalent electric circuit
circuit composed of ideal circuit elements which has, at the terminals or ports, a behaviour
equivalent to that of a given electric or magnetic circuit or device
Note 1 to entry: Equivalent electric circuits can also be used to represent other kinds of devices or phenomena.
[SOURCE: IEC 60050-131:2002, 131-15-07]
3.2
circuit element
in electromagnetism, mathematical model of a device characterized by one or more relations
between integral quantities
[SOURCE: IEC 60050-131:2002, 131-11-03]
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3.3
equivalent circuit of an AC resistor
equivalent electric circuit of an AC resistor
electric circuit which has the same AC characteristics as a resistor, and which would have an
impedance equal to the resistor under specified operating conditions
Note 1 to entry: Specified operating conditions should include working frequency and voltage.
3.4
two-element equivalent circuit of an AC resistor
equivalent circuit of an AC resistor with two elements under specified operating conditions
Note 1 to entry: A two-element equivalent circuit of an AC resistor is given by either an equivalent AC resistance,
R in series with an equivalent inductance, L or an equivalent AC resistance, R in parallel with an equivalent
s s p
capacitance, C (see Annex C).
p
3.5
three-element equivalent circuit of an AC resistor
equivalent electric circuit of an AC resistor with three elements under specified operating
conditions
3.6
equivalent AC resistance of an AC resistor
AC resistance
or R ) which is the AC resistive component of the resistor
value of resistance (R
s p
Note 1 to entry: The AC resistance is usually taken as the equivalent series resistance R , for resistors of
s
, for resistors of Category C (see Annex B).
Category A, and as the equivalent parallel resistance R
p
3.7
terminal pair
port consisting of two terminals such that the electric current directed from an external circuit
or device to one terminal is identical with the current directed from the other terminal to the
external circuit or device
[SOURCE: IEC 60050-131:2002, 131-12-63]
3.8
time constant
τ
-t/τ
time τ in the expression F(t) = A + Be of a quantity F growing or decaying exponentially
-t/τ
towards a constant value A with increasing time t, or in the expression F(t) = A + f(t)e of an
exponentially damped oscillation, where f is a periodic function of time
Note 1 to entry: The time constant of an exponentially varying quantity is the duration of a time interval at the end
of which the absolute value of the difference between the quantity and the limit has decreased to 1/e of the absolute
value of this difference at the beginning of the time interval, where e is the base of natural logarithms.
Note 2 to entry: For a resistor, at any particular frequency, the time constant is defined as either: L /R , or R C
s s p p
whichever yields a positive value (see Annex C). For determining the time constant, the DC resistance may be used
instead of the equivalent AC resistance.
Note 3 to entry: For a resistor using the three-element equivalent circuit expressed, the time constant is
L L
approximately equal to: − CR , or CR− (see Annex C).
R R
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Note 4 to entry: The phase displacement of the current flowing through the resistor from the voltage appearing
L
across it with a time constant L /R or − CR is such that the current is lagging, and that with a time constant R C
s s p p
R
L
or CR− is leading when L and C , have positive values, L and L being expressed in henrys, R , R and R in ohms
s p s s p
R
and C and C in farads.
p
[SOURCE: IEC 60050-103:2009, 103-05-26, modified – The existing Note 2 has been deleted
and a new Note 2, Note 3 and Note 4 to entry have been added to adapt to usage in AC resistor
technology.]
3.9
time constant index
conventional designation of a time constant by a number or symbol
Note 1 to entry: In this document, the time constant index is expressed in seconds using the appropriate SI prefix.
3.10
AC/DC difference
difference between the equivalent AC resistance at a stated frequency and
the DC resistance, expressed as a percentage (%) of the DC resistance
3.11
AC/DC difference index
number which designates the limit of the AC/DC difference in nominal range of use for
frequency, expressed in %
3.12
frequency index
number which designates the upper limit of the nominal range of use for frequency, expressed
in hertz using the appropriate SI prefix
3.13
skin effect
for an alternating electric current in a conductor, phenomenon in which the current density is
greater near the surface than in the interior of the conductor
Note 1 to entry: The skin effect increases the resistance and decreases the inductance of a conductor with the
frequency of the electric current.
Note 2 to entry: The skin effect occurs also in the more general case of any time-varying current.
[SOURCE: IEC 60050-121:1998, 121-13-18]
3.14
residual inductance
inductance value between the points of connection of a multiple or multi-dial AC resistor having
switching devices with a zero position, when all switching elements are set to the zero position
4 Resistor characterization and construction
4.1 Resistor characterization
AC resistors satisfying the requirements of this document are characterized:
a) by classes related to their DC accuracy as specified in IEC 60477-1,
b) by classes related to their equivalent AC resistance as specified in 5.1 or AC/DC difference
indices as specified in 5.1, and
c) by time constant indices as specified in 5.1, and
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d) by frequency indices as specified in Clause 6.
4.2 Resistor construction
Because of the uncertainties in AC properties which can result from stray inductances, stray
capacitances, eddy currents, dielectric absorption effects and skin effects, the AC resistors to
which this document applies are classified according to their construction (see Annex D), as
follows:
a) two-terminal resistor, each terminal being able to be used both for current or potential;
b) three-terminal resistor which has one more shield terminal (can also be called a guard
terminal) connected to the electric screen than the two-terminal resistor to reduce the stray
capacitances effect;
c) four-terminal resistor which has independent current terminals and potential terminals to
reduce the stray inductances and contact resistances;
d) five-terminal resistor which has one more shield terminal than the four-terminal resistor;
e) four-terminal coaxial resistor which has two terminal-pairs with the outer shield conductors
working as the low terminal of current or potential;
f) two-terminal-pair resistor which has two terminal-pairs with the outer shield conductors
working as the return path for the signal current (not grounded);
g) four-terminal-pair resistor which has four terminal-pairs with the outer shield conductors
working as the return path for the signal current (not grounded) to eliminate the effect of
mutual coupling between the current and potential leads.
5 General requirements
5.1 DC resistance, AC resistance and time constant
The DC characteristics of an AC resistor shall be as specified in IEC 60477-1.
The equivalent AC resistance of an AC resistor characterized by class related to the AC
resistance shall comply with the limits of relative uncertainty as specified for their AC resistance
class index in Table 1 at initial calibration.
Table 1 – Limits of the AC resistance relative uncertainty
AC resistance
0,000 01 0,000 02 0,000 05 … 2 5 10
class index
Limits of relative
uncertainty for 0,000 01 % 0,000 02 % 0,000 05 % … 2 % 5 % 10 %
AC resistance
NOTE The value of the AC resistance of a given resistor is somewhat dependent on the frequency at which it is
measured. However, as the purpose here is to classify AC resistors, measurements at 1 kHz (or lower) are
generally adequate.
The AC/DC difference of an AC resistor characterized by AC/DC difference index shall comply
with the limits of AC/DC difference specified for its AC/DC difference index in Table 2 at initial
calibration.
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SIST EN IEC 60477-2:2022
– 10 – IEC 60477-2:2022 © IEC 2022
Table 2 – Limits of the AC/DC difference
AC/DC
0,000 001 0,000 002 0,000 005 … 0,2 0,5 1
difference index
Limits of the
AC/DC ±0,000 001 % ±0,000 002 % ±0,000 005 % … ±0,2 % ±0,5 % ±1 %
difference
NOTE Measurements at 1 kHz (or lower) are here generally adequate.
An AC resistor shall choose either an AC resistance class index or an AC/DC difference index
to show the AC resistance character.
The time constant of an AC resistor shall not exceed the appropriate value of the time constant
index selected from the sequence:
• 1 ns, 2 ns, 5 ns, 10 ns, …100 μs.
NOTE The value of the time constant of a given resistor is also somewhat dependent on the frequency at which it
is measured. Measurements at 1 kHz (or lower) are here generally adequate as with the measurements of AC
resistance.
5.2 Multiple resistors
Multiple resistors, excluding multi-dial resistors, may have a different AC resistance class or
AC/DC difference and time constant index for each selectable value.
For a multiple resistor in which the lowest selectable resistance value is nominally zero, the
manufacturer shall state the value of the residual inductance under this condition.
5.3 Multi-dial resistors
Multi-dial resistors shall have a single AC resistance class index or AC/DC difference index and
a single time constant index for all selectable values on any dial used alone. The several dials
may each have a different AC resistance class index or AC/DC difference index and a different
time constant index.
The AC resistance class index or AC/DC difference index of a given dial shall also apply at any
setting of the dial when that dial is used in conjunction with any setting of any dial(s) inferior to
it in value.
The time constant index of a given dial shall
...
SLOVENSKI STANDARD
oSIST prEN IEC 60477-2:2021
01-julij-2021
Laboratorijski upori - 2. del: Laboratorijski upori za izmenični tok
Laboratory resistors. Part 2: Laboratory AC resistors
Résistances de laboratoire - Partie 2: Résistances de laboratoire à courant alternatif
Ta slovenski standard je istoveten z: prEN IEC 60477-2:2021
ICS:
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
oSIST prEN IEC 60477-2:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN IEC 60477-2:2021
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oSIST prEN IEC 60477-2:2021
85/772/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60477-2 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2021-05-21 2021-08-13
SUPERSEDES DOCUMENTS:
85/735/CD, 85/758/CC
IEC TC 85 : MEASURING EQUIPMENT FOR ELECTRICAL AND ELECTROMAGNETIC QUANTITIES
SECRETARIAT: SECRETARY:
China Ms Guiju HAN
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of
which they are aware and to provide supporting documentation.
TITLE:
Laboratory resistors. Part 2: Laboratory AC resistors
PROPOSED STABILITY DATE: 2025
NOTE FROM TC/SC OFFICERS:
1
Copyright © 2021 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to download this
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
permission in writing from IEC.
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2 CONTENTS
3 FOREWORD . - 3 -
4 1 Scope . - 5 -
5 2 Normative references . - 5 -
6 3 Terms and definitions . - 5 -
7 4 Resistor characterization . - 7 -
8 5 General requirements . - 7 -
9 5.1 DC resistance, AC resistance and time constant . - 7 -
10 5.2 Multiple resistors. - 8 -
11 5.3 Multi-dial resistors . - 8 -
12 5.4 Connecting leads . - 8 -
13 5.5 Conditions for the determination of DC and AC characteristics . - 9 -
14 6 Permissible variations. - 9 -
15 7 Further electrical and mechanical requirements . - 10 -
16 8 Information, markings and symbols . - 10 -
17 8.1 Information . - 10 -
18 8.2 Markings and symbols . - 10 -
19 Annex A (informative) Examples of markings . - 11 -
20 A.1 Example of marking for a single resistor . - 11 -
21 A.2 Example of marking for a five-dial resistor . - 11 -
22 Annex B (informative) General considerations regarding laboratory AC resistors . - 13 -
23 Annex C (informative) Equivalent circuits of an AC resistor . - 14 -
24 Annex D (informative) Construction of AC resistors . - 18 -
25 D.1 Construction and electrical definition of the impedance . - 18 -
26 D.2 Two-terminal resistor . - 18 -
27 D.3 Three-terminal resistor . - 18 -
28 D.4 Four-terminal resistor . - 19 -
29 D.5 Five-terminal resistor . - 19 -
30 D.6 Four-terminal coaxial resistor . - 19 -
31 D.7 Two-terminal-pair resistor . - 20 -
32 D.8 Four-terminal-pair resistor. - 20 -
33
34 Figure A.1 –Example of marking for a single AC resistor . - 11 -
35 Figure A.2 –Example of marking for a five-dial resistor . - 11 -
36 Figure C.1 –The three-element equivalent circuit of AC resistor (Category A) . - 15 -
37 Figure C.2 –The three-element equivalent circuit of AC resistor (Category C) . - 16 -
38 Figure D.1 – Two-terminal resistor . - 18 -
39 Figure D.2 – Three-terminal resistor . - 18 -
40 Figure D.3 – Four-terminal resistor . - 19 -
41 Figure D.4 – Five-terminal resistor . - 19 -
42 Figure D.5 – Four-terminal coaxial resistor . - 20 -
43 Figure D.6 – Two-terminal-pair resistor . - 20 -
44 Figure D.7 – Four-terminal-pair resistor . - 21 -
45
46 Table 1 –limits of the AC resistance relative uncertainty . - 8 -
47 Table 2 –limits of the AC/DC difference . - 8 -
48 Table 3 –Upper limit of the nominal range of use for frequency . - 9 -
49
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50 INTERNATIONAL ELECTROTECHNICAL COMMISSION
51 ____________
52
53 LABORATORY RESISTORS –
54
55 Part 2: Laboratory AC resistors
56
57
58
59 FOREWORD
60 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
61 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
62 international co-operation on all questions concerning standardization in the electrical and electronic fields. To
63 this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
64 Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
65 Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
66 in the subject dealt with may participate in this preparatory work. International, governmental and non-
67 governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
68 with the International Organization for Standardization (ISO) in accordance with conditions determined by
69 agreement between the two organizations.
70 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
71 consensus of opinion on the relevant subjects since each technical committee has representation from all
72 interested IEC National Committees.
73 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
74 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
75 Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
76 misinterpretation by any end user.
77 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
78 transparently to the maximum extent possible in their national and regional publications. Any divergence
79 between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
80 the latter.
81 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
82 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
83 services carried out by independent certification bodies.
84 6) All users should ensure that they have the latest edition of this publication.
85 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
86 members of its technical committees and IEC National Committees for any personal injury, property damage or
87 other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
88 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
89 Publications.
90 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
91 indispensable for the correct application of this publication.
92 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
93 patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
94 International Standard IEC 60477-2 has been prepared by IEC technical committee 85:
95 Measuring equipment for electromagnetic quantities.
96 This second edition cancels and replaces the first edition published in 1979, Amendment
97 1:1997. This edition constitutes a technical revision.
98 This edition includes the following significant technical changes with respect to the previous
99 edition:
100 – replaced a.c. with AC according IEC 60050-151:2001, 151-15-01;
101 – extended the resistor frequency scope to 1 MHz of this document;
102 – updated the classification according the AC resistor construction;
103 – updated the terms and definition according to IEC 60050 series;
104 – added the definition of AC/DC difference of an AC resistor;
105 – added the resistor classification according the AC resistance or AC/DC difference index;
106 – updated the safety symbols and requirements according to IEC 60047;
107 – added the three-element equivalent circuit of an AC resistor in Annex C;
108 – added the annex on constructions of AC resistors.
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109 The text of this International Standard is based on the following documents:
110
FDIS Report on voting
XX/XX/FDIS XX/XX/RVD
111
112 Full information on the voting for the approval of this International Standard can be found in
113 the report on voting indicated in the above table.
114 This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
115 The committee has decided that the contents of this document will remain unchanged until the
116 stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
117 the specific document. At this date, the document will be
118 • reconfirmed,
119 • withdrawn,
120 • replaced by a revised edition, or
121 • amended.
122
123 The National Committees are requested to note that for this document the stability date
124 is 2025.
125 THIS TEXT IS INCLUDED FOR THE INFORMATION OF THE NATIONAL COMMITTEES AND WILL BE
126 DELETED AT THE PUBLICATION STAGE.
127
128
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129 LABORATORY RESISTORS –
130
131 Part 2: Laboratory AC resistors
132
133
134
135 1 Scope
136 This part of IEC 60477 applies to resistors intended as laboratory AC resistors for use over a
137 range of frequencies from DC up to a stated frequency which is not in excess of 1 MHz. Such
138 resistors are hereinafter referred to as “AC resistors”.
139 In addition to satisfying the requirements of IEC 60477, resistors satisfying the requirements
140 of this standard are designed to have a small variation of resistance and a small phase
141 displacement over the stated frequency range.
142 Because of the uncertainties in AC properties which can result from stray inductances, stray
143 capacitances, eddy currents, dielectric absorption effects and skin effect, the AC resistors to
144 which this standard applies are classified according to their construction (see Annex D), as
145 follows:
146 a) Two-terminal resistor which each of one terminal both for current and potential;
147 b) Three-terminal resistor which has one more shield terminal (also could be called as guard
148 terminal) connected to the electric screen than the two-terminal resistor to reduce the
149 stray capacitances effect;
150 c) Four-terminal resistor which has independent current terminals and potential terminals to
151 reduce the stray inductances and contact resistances;
152 d) Five-terminal resistor which has one more shield terminal than the four-terminal resistor;
153 e) Four-terminal coaxial resistor which has two terminal-pairs with the outer shield
154 conductors working as the low terminal of current or potential;
155 f) Two-terminal-pair resistor which has two terminal-pairs with the outer shield conductors
156 working as the return path for the signal current (not grounded);
157 g) Four-terminal-pair resistor which has four terminal-pairs with the outer shield conductors
158 working as the return path for the signal current (not grounded) to eliminate the effect of
159 mutual coupling between the current and potential leads.
160
161 2 Normative references
162 The following documents are referred to in the text in such a way that some or all of their
163 content constitutes requirements of this document. For dated references, only the edition
164 cited applies. For undated references, the latest edition of the referenced document (including
165 any amendments) applies.
166 IEC 60477, Laboratory DC resistors
167 3 Terms and definitions
168 For the purposes of this document, the following terms and definitions apply.
169 ISO and IEC maintain terminological databases for use in standardization at the following
170 addresses:
171 ISO Online browsing platform: available at http://www.iso.org/obp
172 IEC Electropedia: available at http://www.electropedia.org/
173 3.1
174 equivalent electric circuit
175 circuit composed of ideal circuit elements which has, at the terminals or ports, a behaviour
176 equivalent to that of a given electric or magnetic circuit or device
177 Note 1 to entry: Equivalent electric circuits can also be used to represent other kinds of devices or phenomena.
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178 [SOURCE: IEC 60050-131:2002,131-15-07]
179 3.2
180 circuit element
181 in electromagnetism, mathematical model of a device characterized by one or more relations
182 between integral quantities
183 [SOURCE: IEC 60050-131:2002,131-11-03]
184 3.3
185 equivalent circuit of an AC resistor
186 electrical electric circuit which has the same AC characteristics as a resistor, would have an
187 impedance equal to the resistor under specified operating conditions
188 Note 1 to entry: Specified operating conditions should include working frequency and voltage.
189 3.4
190 two-element equivalent circuit of an AC resistor
191 an equivalent circuit of an AC resistor with two elements under specified operating conditions
192 Note 1 to entry: two-element equivalent circuit of an AC resistor is given by either an equivalent AC resistance,
193 R in series with an equivalent inductance, L or an equivalent AC resistance, R in parallel with an equivalent
s s p
194 capacitance, C (see Annexes C)
p .
195 3.5
196 three-element equivalent circuit of an AC resistor
197 an equivalent electric circuit of an AC resistor with three elements under specified operating
198 conditions
199 3.6
200 equivalent AC resistance of an AC resistor
201 AC resistance
202 value of resistance (R or R ) which is the AC resistive component of the resistor
s p
203 Note 1 to entry: The AC resistance is usually taken as the equivalent series resistance R , for resistors Category
s
204 A, and as the equivalent parallel resistance R , for resistors Category C (see Annexes B).
p
205 3.7
206 terminal pair
207 port consisting of two terminals such that the electric current directed from an external circuit
208 or device to one terminal is identical with the current directed from the other terminal to the
209 external circuit or device
210 [SOURCE: IEC 60050-131:2002,131-12-63]
211 3.8
212 time constant
213 τ
−tτ
F t A+Be
214 time τ in the expression () of a quantity F growing or decaying exponentially
−tτ
215 towards a constant value A with increasing time t, or in the expression F t A+ f t e of
() ()
216 an exponentially damped oscillation, where f is a periodic function of time
217 Note 1 to entry: for a quantity growing or decaying exponentially towards a constant value the duration of a time
218 interval, at the end of which the absolute value of the difference between that constant value and the value of the
–1
219 variable quantity has decreased to e times of the absolute value of the difference at the beginning of the interval,
220 where e is the base of natural logarithms.
221 Note 2 to entry: For resistor, at any particular frequency, it is defined as either: L /R , or R C whichever yields a
s s p p
222 positive value (see Appendix C). For determining the time constant, the DC resistance may be used instead of the
223 equivalent AC resistance.
224 Note 3 to entry: For resistor used three-element equivalent circuit expressed, it is approximately equal to:
L
L
225 , or (see Appendix C) .
CR−
−CR
R R
226 Note 4 to entry: The phase displacement of the current flowing through the resistor from the voltage appearing
L
227 across it with a time constant L /R or is such that the current is lagging, and that with a time constant
s s
−CR
R
=
=
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L
228 R C or is leading when L and C , have positive value, L and L being expressed in henrys, R , R and R
p p s p s s p
CR−
R
229 in ohms and C and C in farads.
p
230 [SOURCE: IEC 60050-103:2009, 103-05-26, modified – Note 2, Note 3 and Note 4 to entry
231 has been added to adapt to usage in AC resistor technology]
232 3.9
233 time constant index
234 conventional designation of a time constant by a number or symbol
235 Note 1 to entry: In this standard, it is expressed in seconds using the appropriate SI prefix.
236 3.10
237 AC/DC difference
238 difference between the equivalent AC resistance at a stated frequency and the DC resistance,
239 expressed in percentage (%) of the DC resistance
240 3.11
241 AC/DC difference index
242 number which designates the limit of the AC/DC difference with in nominal range of use for
243 frequency, expressed in %
244 3.12
245 frequency index
246 number which designates the upper limit of the nominal range of use for frequency, expressed
247 in hertz (see Table 3) using the appropriate SI prefix
248 3.13
249 skin effect
250 for an alternating electric current in a conductor, phenomenon in which the current density is
251 greater near the surface than in the interior of the conductor
252 Note 1 to entry: The skin effect increases the resistance and decreases the inductance of a conductor with the
253 frequency of the electric current.
254 Note 2 to entry: The skin effect occurs also in the more general case of any time-varying current.
255 [SOURCE: IEC 60050-121:1998, 121-13-18]
256 3.14
257 residual inductance
258 inductance value between the points of connection of a multiple or multi-dial AC resistor
259 having switching devices with a zero position, when all switching elements are set to the zero
260 position
261 4 Resistor characterization
262 AC resistors satisfying this standard are characterized:
263 h) by classes related to their DC accuracy as specified in IEC 60477,
264 i) by classes related to their equivalent AC resistance as specified in Sub clause 5.1.2 or
265 AC/DC difference indices as specified in Sub-clause 5.1.3 and,
266 j) by time constant indices as specified in Sub-clause 5.1.4 and,
267 k) by frequency indices as specified in Sub-clause 6.2.
268
269 5 General requirements
270 5.1 DC resistance, AC resistance and time constant
271 The DC characteristics of an AC resistor shall be as specified in IEC 60477.
272 The equivalent AC resistance of an AC resistor characterized by class related to the AC
273 resistance shall comply with the limits of relative uncertainty for specified for their AC
274 resistance class index in Table 1 at initial calibration.
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275 Table 1 –limits of the AC resistance relative uncertainty
AC resistance
0.00001 0.00002 0.00005 … 2 5 10
class index
limits of relative
uncertainty for 0.00001% 0.00002% 0.00005% … 2% 5% 10%
AC resistance
276 Note 1 The value of the AC resistance of a given resistor is somewhat dependent on the frequency at which it is
277 measured. However, as the purpose here is to affect a classification of resistors, measurements at 1 kHz (or lower)
278 are here generally adequate.
279 The AC/DC difference of an AC resistor characterized by AC/DC difference index shall comply
280 with the limits of AC/DC difference specified for their AC/DC difference index in Table 2 at
281 initial calibration.
282 Table 2 –limits of the AC/DC difference
AC/DC
0.000001 0.000002 0.000005 … 0.2 0.5 1
difference index
limits of the
AC/DC ±0.000001% ±0.000002% ±0.000005% … ±0.2% ±0.5% ±1%
difference
283 Note 2 Measurements at 1 kHz (or lower) are here generally adequate.
284 Note 3 An AC resistor shall choose either AC resistance class index or AC/DC difference index to show the
285 equivalent AC resistance character.
286 The time constant of an AC resistor shall not exceed the appropriate value of the time
287 constant index selected from the sequence:
288 • 1 ns, 2 ns, 5 ns, 10 ns, …100 μs.
289 Note 4 The value of the time constant of a given resistor is also somewhat dependent on the frequency at which it
290 is measured. Measurements at 1 kHz (or lower) are here generally adequate as same as the measurements of AC
291 resistance.
292 5.2 Multiple resistors
293 Multiple resistors, excluding multi-dial resistors, may have different AC resistance class or
294 AC/DC difference and time constant index for each selectable value.
295 For a multiple resistor in which the lowest selectable resistance value is nominally zero, the
296 manufacturer shall state the value of the residual inductance under this condition.
297 5.3 Multi-dial resistors
298 Multi-dial resistors shall have a single AC resistance class index or AC/DC difference index
299 and a single time constant index for all selectable values on any dial used alone. The several
300 dials may each have a different AC resistance class index or AC/DC difference index and a
301 different time constant index.
302 The AC resistance class index or AC/DC difference index of a given dial shall also apply at
303 any setting of the dial when that dial is used in conjunction with any setting of any dial(s)
304 inferior to it in value.
305 The time constant index of a given dial shall also apply at any setting of the dial when that
306 dial is used in conjunction with any setting of any dial(s) inferior to it in value.
307 5.4 Connecting leads
308 Separate current and potential connections shall be made to a resistor having a pair of
309 terminals for each port of connection, unless other conditions are stated by the manufacturer.
310 The mutual inductances between the current and potential leads and between each of these
311 leads and the resistor shall be minimized.
312 The leads making connection to a resistor having a single terminal for each port of connection
313 shall be arranged so as to minimize their inductance.
314 Note 1 This is particularly important for resistors of values of 10Ω and lower.
315 The leads making connection to a resistor shall not alter significantly the equivalent parallel
316 capacitance, if necessary, by the provision of screen for each lead and by the use of an
317 appropriate measuring circuit.
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318 Note 2 The magnitude of capacitance that will cause a significant alteration will depend upon the value of the
319 resistance and the time constant.
320 5.5 Conditions for the determination of DC and AC characteristics
321 All tests of DC characteristics shall be carried out as specified in IEC 60477
322 Note 1 At low frequencies, the uncertainty of an AC resistor is essentially the same as its uncertainty at DC
323 Note 2 At higher frequencies, an additional variation as specified by Sub-clause 6.1 is permitted.
324 All tests of AC characteristics shall be carried out under the reference conditions specified in
325 IEC 60477.
326 The AC resistance of an AC resistor shall be measured at a frequency of 1 kHz or at the
327 frequency corresponding to its frequency index if the latter is lower (see Clause 6).
328 The time constant of an AC resistor shall be measured at a frequency of 1 kHz or at the
329 frequency corresponding to its frequency index if the latter is lower (see Clause 6).
330 The residual inductance of an AC resistor (see Sub-clause 5.2.2) shall be measured with the
331 resistor connected as in normal use and at a frequency of 1 kHz or at the frequency
332 corresponding to its frequency index if the latter is lower (see Clause 6).
333 A resistor having a shield terminal (see Items b) and d) of Sub-clause 1.3) shall be tested with
334 the screen connected as specified by the manufacturer.
335 A resistor not having a shield terminal (see Item a) and c) of Sub-clause 1.3) shall be tested
336 within an earthed conductive enclosure as specified by the manufacturer. If this enclosure is
337 not specified, the resistor shall be tested within an earthed conductive enclosure separated
338 from the surface of the resistor by between 10 mm and 20 mm at all places.
339 A resistor having terminal-pairs (see Items e), f) and g) of Sub-clause 1.3) shall be tested with
340 the terminal-pair connected as specified by the manufacturer.
341 Any other necessary conditions shall be stated by the manufacturer.
342 When necessary, details of the testing method shall be agreed between the manufacturer and
343 the user.
344 6 Permissible variations
345 Changes in influence quantities over the nominal ranges of use specified in IEC 60477 will
346 cause no significant effect on the AC characteristics of the resistor. Requirements relating to
347 variations of AC characteristics other than those due to frequency are therefore not included
348 in this standard.
349 The upper limit of the nominal range of use for frequency shall be designated using the
350 appropriate frequency index selected from Table 3.
351 Tabl
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