IEC 62812:2019

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

Mesures de faibles résistances – Méthodes et recommandations

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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

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
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with the International Organization for Standardization (ISO) in accordance with con
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