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.<\/p>\n
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.<\/p>\n
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.<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 2<\/td>\n | National foreword <\/td>\n<\/tr>\n | ||||||
| 5<\/td>\n | Annex ZA(normative)Normative references to international publicationswith their corresponding European publications <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | 1 Scope 2 Normative references 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 4 Resistance measurement phenomena 4.1 General 4.2 Lead and contact resistance <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | Figures Figure 1 \u2013 Resistance measurement using two-wire sensing <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 4.3 Self-heating <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 4.4 Variation of resistance with temperature Figure 2 \u2013 Variation of resistance with temperature (random example) <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | Figure 3 \u2013 Resistances on a resistor with lead wires <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | 4.5 Thermoelectric e.m.f. Figure 4 \u2013 SMD chip resistor on a PCB <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | Figure 5 \u2013 Thermoelectric e.m.f. Tables Table 1 \u2013 Relative Seebeck coefficients of selected metals <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | Figure 6 \u2013 Thermocouples on a resistor with lead wires <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 4.6 Peltier effect Figure 7 \u2013 Resistance measurement affected by thermoelectric e.m.f. <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 5 Methods of measurement 5.1 General 5.2 Four-wire resistance measurement <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | Figure 8 \u2013 Four-wire resistance measurement <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 5.3 Offset compensation method Figure 9 \u2013 Offset compensation method for resistance measurement <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | Figure 10 \u2013 Current and voltage in the offset compensation method <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | 5.4 Current inversion method Figure 11 \u2013 Current inversion method for resistance measurement <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | Figure 12 \u2013 Current and voltage in the current inversion method <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | 5.5 Differential current inversion method <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | Figure 13 \u2013 Current and voltage in the differential current inversion method <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | 5.6 Short-term trigger method <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | Figure 14 \u2013 Example of resistor specimen <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | 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 \u2013 Connecting leaded resistors in a test fixture <\/td>\n<\/tr>\n | ||||||
| 38<\/td>\n | 6.2 Resistors with solder terminations for surface mount assembly 6.2.1 Connecting SMD resistors on a test substrate Figure 16 \u2013 Resistance of cylindrical copper lead wires <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | Figure 17 \u2013 Soldering pad of test substrate for Kelvin (four-point) connections <\/td>\n<\/tr>\n | ||||||
| 40<\/td>\n | 6.2.2 Connecting SMD resistors in a test fixture Figure 18 \u2013 Resistance of PCB conductor tracks with 35 \u00b5m copper thickness <\/td>\n<\/tr>\n | ||||||
| 41<\/td>\n | 7 Information to be given in the relevant component specification Figure 19 \u2013 Example for connecting SMD resistors on a test fixture <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | Annex A (normative) Letter symbols and abbreviated terms A.1 Letter symbols Table A.1 \u2013 Letter symbols <\/td>\n<\/tr>\n | ||||||
| 43<\/td>\n | A.2 Abbreviated terms <\/td>\n<\/tr>\n | ||||||
| 44<\/td>\n | 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 <\/td>\n<\/tr>\n | ||||||
| 45<\/td>\n | Figure B.1 \u2013 Lengths of soldering pad Figure B.2 \u2013 Position of voltage sense conductor <\/td>\n<\/tr>\n | ||||||
| 46<\/td>\n | B.2.2 Test method Table B.1 \u2013 Thickness of solder printing screen <\/td>\n<\/tr>\n | ||||||
| 47<\/td>\n | B.3 Measurement result and studies Table B.2 \u2013 Table of test conditions <\/td>\n<\/tr>\n | ||||||
| 48<\/td>\n | Figure B.3 \u2013 Thickness of the solder printing screen and position of sense line Figure B.4 \u2013 Position of voltage-sensing line <\/td>\n<\/tr>\n | ||||||
| 49<\/td>\n | Figure B.5 \u2013 Soldering pad length Figure B.6 \u2013 Recommended soldering pad <\/td>\n<\/tr>\n | ||||||
| 50<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Low resistance measurements. Methods and guidance<\/b><\/p>\n |