BS EN IEC 62812:2019
$198.66
Low resistance measurements. Methods and guidance
| Published By | Publication Date | Number of Pages |
| BSI | 2019 | 52 |
Resistance measurements are typically compromised by a variety of phenomena, for example serial resistance in the measurement path, self-heating or non-ohmic properties. Whether the effect of such phenomena on a resistance measurement is acceptable or not depends on the magnitude of each effect in comparison to the resistance and to the required accuracy. Hence, the risk of erroneous resistance measurements increases with decreasing resistance and with a tightening of the permissible tolerance.
This document 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.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | National foreword |
| 5 | Annex ZA(normative)Normative references to international publicationswith their corresponding European publications |
| 7 | English CONTENTS |
| 9 | FOREWORD |
| 11 | 1 Scope 2 Normative references 3 Terms and definitions |
| 12 | 4 Resistance measurement phenomena 4.1 General 4.2 Lead and contact resistance |
| 13 | Figures Figure 1 – Resistance measurement using two-wire sensing |
| 14 | 4.3 Self-heating |
| 15 | 4.4 Variation of resistance with temperature Figure 2 – Variation of resistance with temperature (random example) |
| 16 | Figure 3 – Resistances on a resistor with lead wires |
| 17 | 4.5 Thermoelectric e.m.f. Figure 4 – SMD chip resistor on a PCB |
| 18 | Figure 5 – Thermoelectric e.m.f. Tables Table 1 – Relative Seebeck coefficients of selected metals |
| 19 | Figure 6 – Thermocouples on a resistor with lead wires |
| 20 | 4.6 Peltier effect Figure 7 – Resistance measurement affected by thermoelectric e.m.f. |
| 21 | 5 Methods of measurement 5.1 General 5.2 Four-wire resistance measurement |
| 22 | Figure 8 – Four-wire resistance measurement |
| 24 | 5.3 Offset compensation method Figure 9 – Offset compensation method for resistance measurement |
| 25 | Figure 10 – Current and voltage in the offset compensation method |
| 27 | 5.4 Current inversion method Figure 11 – Current inversion method for resistance measurement |
| 28 | Figure 12 – Current and voltage in the current inversion method |
| 30 | 5.5 Differential current inversion method |
| 31 | Figure 13 – Current and voltage in the differential current inversion method |
| 33 | 5.6 Short-term trigger method |
| 36 | Figure 14 – Example of resistor specimen |
| 37 | 6 Connecting the specimen 6.1 Resistors with lead wires for soldered assembly 6.1.1 Connecting leaded resistors in a test fixture Figure 15 – Connecting leaded resistors in a test fixture |
| 38 | 6.2 Resistors with solder terminations for surface mount assembly 6.2.1 Connecting SMD resistors on a test substrate Figure 16 – Resistance of cylindrical copper lead wires |
| 39 | Figure 17 – Soldering pad of test substrate for Kelvin (four-point) connections |
| 40 | 6.2.2 Connecting SMD resistors in a test fixture Figure 18 – Resistance of PCB conductor tracks with 35 µm copper thickness |
| 41 | 7 Information to be given in the relevant component specification Figure 19 – Example for connecting SMD resistors on a test fixture |
| 42 | Annex A (normative) Letter symbols and abbreviated terms A.1 Letter symbols Table A.1 – Letter symbols |
| 43 | A.2 Abbreviated terms |
| 44 | Annex B (informative) Test results of soldering pad with Kelvin connection for surface mount resistors B.1 General B.2 Test procedures B.2.1 Test substrates |
| 45 | Figure B.1 – Lengths of soldering pad Figure B.2 – Position of voltage sense conductor |
| 46 | B.2.2 Test method Table B.1 – Thickness of solder printing screen |
| 47 | B.3 Measurement result and studies Table B.2 – Table of test conditions |
| 48 | Figure B.3 – Thickness of the solder printing screen and position of sense line Figure B.4 – Position of voltage-sensing line |
| 49 | Figure B.5 – Soldering pad length Figure B.6 – Recommended soldering pad |
| 50 | Bibliography |
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BS EN IEC 62812:2019:2020 Edition
Low resistance measurements. Methods and guidance Published By Publication Date Number of Pages BSI 2020…
