Callendar-Van Dusen equation

The Callendar-Van Dusen equation is an equation that describes the relationship between resistance (R) and temperature (t) of platinum resistance thermometers.

For the range between -200 °C to 0 °C the equation is

:$R(t)\; =\; R(0)\; [\; 1\; +\; A*t\; +\; B*t^2\; +\; (t\; -\; 100)C*t^3]\; .$

For the range between 0 °C to 661 °C the equation is

:$R(t)\; =\; R(0)\; (\; 1\; +\; A*t\; +\; B*t^2).$

These equations are listed as the basis for the temperature/resistance tables for platinum resistance thermometers and are not intended to be used for the calibration of individual thermometers.

The coefficients for individual thermometers ($A(t)$ and $B(t)$) can be obtained by calibration.

The equation was found by British physicist Hugh Longbourne Callendar, and refined by M. S. Van Dusen.