All heat flux sensors are equipped with at least two tin coated connections which are designed for soldering of measuring leads.
The thickness tolerance of the sensors is 10 %.
Die Toleranz der sonstigen Abmessungen beträgt 0,5 mm.
Der Biegeradius der flexiblen Typen 2 und 6 sollte 20 mm nicht unterschreiten.
The thermal conductivity averaged over the whole volume is between
![Rendered by QuickLaTeX.com \lambda = 0,2...0,3\frac{W}{m \cdot K}](https://www.phymeas.de/wp-content/ql-cache/quicklatex.com-c259b8c91b2574f7494e401fd782fb99_l3.svg)
The operational temperature range of our sensors (-40°C…+80°C) is limited by the thermal stability of the used materials.
Each sensor is delivered with a calibration value determined at 23°C. The expanded (k=2) uncertainty is less than 5%.
The temperature-dependent change of the calibration value c is approximately linear between 0°C…50°C. It can be described by:
![Rendered by QuickLaTeX.com c\left ( \vartheta \right )= c\left ( 1+\alpha \cdot \left ( \vartheta-23^\circ C \right ) \right )](https://www.phymeas.de/wp-content/ql-cache/quicklatex.com-b5adfa4e4520702d1fd1343c9b3c0869_l3.svg)
For the types 1, 3, 7 and 8 (all inflexible types):
![Rendered by QuickLaTeX.com \alpha = -1,17\cdot 10^{-3} K^{-1}](https://www.phymeas.de/wp-content/ql-cache/quicklatex.com-971df6d842c32101505b43c6b48befeb_l3.svg)
For the types 2 and 6 (silicone):
![Rendered by QuickLaTeX.com \alpha = -1.7\cdot 10^{-3} K^{-1}](https://www.phymeas.de/wp-content/ql-cache/quicklatex.com-1fdeb6f631c120af318f13de221b8d06_l3.svg)
To minimize the diffusion of water into the sensor the surfaces of the types 1, 3, 7 are sealed with a thin wax layer.