Evaluation of the uncertainty component due to resistance measurement in the calibration of PRTs at the Al freezing point
K. Yamazawa, K. Harada, M. Arai · 2003
The uncertainty component due to resistance measurement in determining the resistance ratio W(=R/sub tal//R/sub tpw/) at Al freezing point is evaluated. The sources of uncertainty dealt are, (1) the accuracy of the bridge, (2) the non-linearity of the current applied in the measuring bridge, (3) the non-linearity of the bridge reading value, (4) the difference among different measuring bridges and (5) the short-term stability of the standard resistor. The uncertainty value is found to depend on the structures of thermometers.