Influence of measurement current on thermistor test results

Purpose This study aims to investigate the critical yet unregulated parameter of measurement current in thermistor thermometry. Focusing on quantifying the self-heating effect’s influence on measurement accuracy, it establishes operational guidelines for current selection in precision temperature measurements at metrological reference points. Design/methodology/approach Through systematic experimental research, three distinct thermistor thermometers were evaluated at two International Temperature Scale fixed points: water triple point (0.01 °C) and gallium melting point (29.7646 °C). The experimental design incorporated parametric analysis of measurement current variations, with particular emphasis on characterising the relationship between electrical power dissipation and resultant temperature measurement deviations. Findings The experimental results revealed a linear correlation between power dissipation and measurement deviations, demonstrating that maintaining dissipation power below 5 µW limits measurement errors to within 1 mK. However, this study also identified a practical trade-off: while lower currents reduce self-heating effects, they simultaneously increase measurement system complexity and implementation challenges. Originality/value This research provides systematic quantification of measurement current impacts across different thermistor types at primary temperature standards. The established 5 µW power dissipation threshold offers concrete operational guidance for metrological applications. Furthermore, the proposed methodology for balancing measurement accuracy against technical feasibility presents novel insights for precision temperature measurement system design.