Measuring element, tolerance
WIKA uses the following standard elements in the TF35 series:
- NTC, R25 = 2.5 kΩ ±5 %
- NTC, R25 = 10 kΩ ±5 %
- Pt100, class B per DIN EN 60 751
- Pt1000, class B per DIN EN 60 751
- Ni1000, DIN 43 760
Others on request
Platinum elements offer the advantage of meeting international standards (IEC 751 / DIN EN 60 751).
Nickel elements are also standardised, but not international. Due to material- and production-specific criteria, an standardisation of semiconductor elements, e.g. NTC’s and KTY, is not possible. For this reason their interchange ability is limited.
Further advantages of platinum elements are: better long term stability and better behaviour over temperature cycles, a wider temperature range as well as a high accuracy and linearity.
High accuracy and linearity are also possible with NTC’s, but only in a limited temperature range.