Thermal Developments International Ltd TDI TDI manufacture coil wound platinum resistance temperature detectors. These are purchased by sensor manufacturers who build complete resistance thermometers from our detectors. We do not produce complete thermometer assemblies. We produce a range of partially supported Platinum Resistance Temperature Detectors to the highest international standards. TDI Quality The quality control is guaranteed by Isothermal Technology whose UKAS Laboratory provides comparisons to National Standards and indeed directly to ITS-90. TDI  Stable Construction  The construction chosen gives the best compromise between ruggedness and stability of any of the industrially available Platinum Resistance Detectors. TDI  Types Available  All TDI detectors are wire wound platinum resistance types, ceramic housed. Known by a variety of names and terms including temperature detectors, PRTD, (Platinum resistance temperature detectors) RTD or RTDS (resistance temperature detectors). Most PRTDs are constructed to have a nominal resistance of 100 Ohms at 0°C Pt100 but almost any value between 1 Ohm to 1000 Ohm can be made including 25 Ohm and 100 Ohm, Pt25 and Pt1000. - types include Pt25, Pt100 and Pt1000. TDI temperature detectors comply with the requirements of EN 60751 TDI  Tolerances  EN 60751 specifies Class A and Class B, many customers specify tighter tolerances, typically specified as a fraction of the norm, for example 1/10th DIN. TDI always selects detectors at a tighter tolerance than that required by international standards. Please refer to the TDI Catalogue for more data