5698-25 Working Standard SPRT

True Standard Platinum Resistance Thermometer for Reliable Laboratory Performance

Accurate, Trusted, and Fully Specified for Your Lab

The Fluke 5698-25 Working Standard Standard Platinum Resistance Thermometer (SPRT) is designed for those who demand uncompromising accuracy, stability, and transparency in their laboratory temperature standards. Fully compliant with ITS-90 requirements and meticulously engineered for long-term reliability, the 5698-25 is the ideal choice for transferring standards from calibration labs to working labs and for supporting critical measurement processes.

Key Features and Benefits

• True ITS-90 Standard – Meets the full resistance ratio requirements for SPRTs under the International Temperature Scale of 1990 (ITS-90), ensuring the highest level of traceability and measurement confidence.
• Wide Measurement Range – With a temperature range from –200 °C to 670 °C, the 5698-25 covers most laboratory, industrial, and research calibration needs.
• Exceptional Stability and Low Drift – Typical long-term drift is less than 3 mK (and guaranteed below 6 mK) at the triple point of water after 100 hours at 670 °C—ensuring reliable performance over time.
• Strain-Free Platinum Sensor – The sensing element is made from high-purity platinum wire, wound in a completely strain-free configuration on a fused silica cross frame, then annealed and tested for optimum stability.
• Robust, Sealed Construction – Features a 485-mm fused silica sheath, pressure sealed with a special argon/oxygen gas mix, convection prevention discs to reduce stem errors, and a terminal box handle with strain relief. Wires are terminated with gold-plated spade lugs for secure connections.
• Easy Compatibility – Works seamlessly with Fluke 1594A/1595A Super-Thermometer, 1560 Black Stack, or 1529 Chub-E4 Thermometer readouts, thanks to its standard 25-ohm resistance and 1 mA excitation current requirement.
• Flexible Calibration Options – Available with or without calibration. Calibrations are performed in Fluke’s NVLAP-accredited lab using fixed-point or comparison methods, providing full ITS-90 traceability and maximum value for your investment.

Designed as a Working Standard

• What is a Working Standard? – A working standard is used to transfer the ITS-90 from a national or standards laboratory to your facility. The 5698-25 is carefully calibrated against intrinsic references, making it the backbone of your lab’s traceability chain.
• Application Flexibility – Suited for both standards transfer and daily calibration tasks, with robust construction to withstand routine use in busy calibration environments.

Transparent, Reliable, and Supported

• Full Performance Specifications Provided – Unlike some manufacturers, Fluke publishes complete specifications for the 5698-25, so you know exactly what you’re getting before you buy.
• Comprehensive Support – Benefit from Fluke Calibration’s renowned post-purchase support and calibration service options, ensuring your working standard maintains the best possible performance for years to come.