EN IEC 62812:2019

Low resistance measurements - Methods and guidance

IEC 62812:2019 specifies methods of measurement and associated test conditions that eliminate or reduce the influence of adverse phenomena in order to improve the attainable accuracy of low-resistance measurements. The methods described in this document are applicable for the individual measurements of the resistance of individual resistors, and also for resistance measurements as part of a test sequence. They are applied if prescribed by a relevant component specification, or if agreed between a customer and a manufacturer.

Messung niederohmiger Widerstände - Verfahren und Leitfaden

Mesures de faibles résistances - Méthodes et recommandations

L'IEC 62812:2019 spécifie les méthodes de mesure et les conditions d'essai associées qui éliminent ou réduisent l'influence des phénomènes défavorables afin d'améliorer la précision réalisable des mesures de faibles résistances. Les méthodes décrites dans le présent document s'appliquent aux mesures individuelles de la valeur de résistances individuelles, ainsi qu'aux mesures de résistances dans le cadre d'une séquence d'essai. Elles sont appliquées si elles sont prescrites par une spécification de composant pertinente ou si elles font l'objet d'un accord entre un client et un fabricant.

Meritve nizke upornosti - Metode in navodila (IEC 62812:2019)

Na meritve upornosti običajno vplivajo različni pojavi, na primer serijska upornost na poti merjenja, samosegrevanje ali neohmske lastnosti. Če je vpliv teh pojavov na merjenje upornosti sprejemljiv ali ne, je odvisno od obsega posameznega učinka v primerjavi z upornostjo in zahtevano natančnostjo. Tako se tveganje za napačne meritve upornosti poveča z zmanjšano upornostjo in zaostrovanjem dopustnega odstopanja.
Ta dokument določa merilne metode in povezane preskusne pogoje za odpravo ali zmanjšanje vpliva škodljivih pojavov, da bi izboljšali dosegljivo natančnost meritev nizke upornosti.
Metode, ki so opisane v tem dokumentu, se uporabljajo za posamezne meritve upornosti posameznih uporov ter za meritve upornosti kot del preskusnega zaporedja. Metode se uporabljajo, če jih predpisuje specifikacija ustreznega sestavnega dela ali se o tem dogovorita kupec in proizvajalec.

General Information

• Status: Published
• Publication Date: 04-Jul-2019
• Withdrawal Date: 05-Jun-2022
• ICS: 31.040.01 - Resistors in general
• Technical Committee: CLC/TC 40XB - CLC/TC 40XB
• Drafting Committee: IEC/TC 40 - IEC_TC_40
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 05-Jul-2019
• Completion Date: 05-Jul-2019
• Ref Project: SIST EN IEC 62812:2019 - Low resistance measurements - Methods and guidance (IEC 62812:2019)

Relations

• Corrected By: EN IEC 62812:2019/AC:2020-04 - Low resistance measurements - Methods and guidance
• Effective Date: 31-Mar-2020

Standards Content (Sample)

SLOVENSKI STANDARD
01-oktober-2019
Meritve nizke upornosti - Metode in navodila (IEC 62812:2019)
Low resistance measurements - Methods and guidance (IEC 62812:2019)
Messung niederohmiger Widerstände - Verfahren und Leitfaden (IEC 62812:2019)
Mesures de faibles résistances - Méthodes et recommandations (IEC 62812:2019)
Ta slovenski standard je istoveten z: EN IEC 62812:2019
ICS:
31.040.01 Upori splošno Resistors in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 62812

NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2019
ICS 31.040.01
English Version
Low resistance measurements - Methods and guidance
(IEC 62812:2019)
Mesures de faibles résistances - Méthodes et Messung niederohmiger Widerstände - Verfahren und
recommandations Leitfaden
(IEC 62812:2019) (IEC 62812:2019)
This European Standard was approved by CENELEC on 2019-06-06. 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 62812:2019 E
European foreword
The text of document 40/2665/FDIS, future edition 1 of IEC 62812, prepared by IEC/TC 40
"Capacitors and resistors for electronic equipment" was submitted to the IEC-CENELEC parallel vote
and approved by CENELEC as EN IEC 62812:2019.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2020-03-06
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2022-06-06
document have to be withdrawn
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 62812:2019 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 60115-2 NOTE Harmonized as EN 60115-2
IEC 60115-8 NOTE Harmonized as EN 60115-8
IEC 60301 NOTE Harmonized as EN 60301
IEC 61249-5-1 NOTE Harmonized as EN 61249-5-1

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 60068-1 -  Environmental testing - Part 1: General and guidance EN 60068-1 -
IEC 60115-1 (mod) 2008 Fixed resistors for use in electronic equipment - Part EN 60115-1 2011
1: Generic specification
- -   + A11 2015
IEC 60294 -  Measurement of the dimensions of a cylindrical EN 60294 -
component with axial terminations

IEC 62812 ®
Edition 1.0 2019-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low resistance measurements – Methods and guidance

Mesures de faibles résistances – Méthodes et recommandations

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.040.01 ISBN 978-2-8322-6870-4

– 2 – IEC 62812:2019 © IEC 2019
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Resistance measurement phenomena . 7
4.1 General . 7
4.2 Lead and contact resistance . 7
4.3 Self-heating . 9
4.4 Variation of resistance with temperature . 10
4.5 Thermoelectric e.m.f. . 12
4.6 Peltier effect . 15
5 Methods of measurement . 16
5.1 General . 16
5.2 Four-wire resistance measurement . 16
5.3 Offset compensation method . 19
5.4 Current inversion method . 22
5.5 Differential current inversion method . 25
5.6 Short-term trigger method . 28
6 Connecting the specimen . 32
6.1 Resistors with lead wires for soldered assembly . 32
6.1.1 Connecting leaded resistors in a test fixture . 32
6.2 Resistors with solder terminations for surface mount assembly . 33
6.2.1 Connecting SMD resistors on a test substrate. 33
6.2.2 Connecting SMD resistors in a test fixture . 35
7 Information to be given in the relevant component specification . 36
Annex A (normative) Letter symbols and abbreviated terms . 37
A.1 Letter symbols . 37
A.2 Abbreviated terms . 38
Annex B (informative) Test results of soldering pad with Kelvin connection for surface
mount resistors . 39
B.1 General . 39
B.2 Test procedures . 39
B.2.1 Test substrates . 39
B.2.2 Test method . 41
B.3 Measurement result and studies . 42
Bibliography . 45

Figure 1 – Resistance measurement using two-wire sensing . 8
Figure 2 – Variation of resistance with temperature (random example) . 10
Figure 3 – Resistances on a resistor with lead wires . 11
Figure 4 – SMD chip resistor on a PCB . 12
Figure 5 – Thermoelectric e.m.f. . 13
Figure 6 – Thermocouples on a resistor with lead wires . 14
Figure 7 – Resistance measurement affected by thermoelectric e.m.f. . 15

IEC 62812:2019 © IEC 2019 – 3 –
Figure 8 – Four-wire resistance measurement . 17
Figure 9 – Offset compensation method for resistance measurement . 19
Figure 10 – Current and voltage in the offset compensation method . 20
Figure 11 – Current inversion method for resistance measurement . 22
Figure 12 – Current and voltage in the current inversion method . 23
Figure 13 – Current and voltage in the differential current inversion method . 26
Figure 14 – Example of resistor specimen. 31
Figure 15 – Connecting leaded resistors in a test fixture . 32
Figure 16 – Resistance of cylindrical copper lead wires . 33
Figure 17 – Soldering pad of test substrate for Kelvin (four-point) connections . 34
Figure 18 – Resistance of PCB conductor tracks with 35 µm copper thickness. 35
Figure 19 – Example for connecting SMD resistors on a test fixture . 36
Figure B.1 – Lengths of soldering pad . 40
Figure B.2 – Position of voltage sense conductor . 40
Figure B.3 – Thickness of the solder printing screen and position of sense line . 43
Figure B.4 – Position of voltage-sensing line. 43
Figure B.5 – Soldering pad length . 44
Figure B.6 – Recommended soldering pad . 44

Table 1 – Relative Seebeck coefficients of selected metals. 13
Table A.1 – Letter symbols . 37
Table B.1 – Thickness of solder printing screen . 41
Table B.2 – Table of test conditions . 42

– 4 – IEC 62812:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW RESISTANCE MEASUREMENTS –
METHODS AND GUIDANCE
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
...