Resistance thermometer 5686-B

RTDplatinum resistiveplatinum

Product overview
The 5686-B Glass Capsule Standard Platinum Resistance Thermometer (SPRT) is a miniature, fully immersible primary standard instrument for converting temperature to resistance with metrology-grade accuracy. ITS-90 compliant, the 5686-B is designed for laboratory and field calibrations where a compact SPRT is required.

Key features

• Miniature glass capsule SPRT for metrology applications needing small probes.
• Temperature range: –260 °C (13 K) to 232 °C (505 K) with typical stability of 0.001 °C over a 100 °C span.
• Suitable for cryogenics, calorimetry and confined-volume calibrations where long-stem SPRTs are impractical.
• True SPRT construction: high-purity platinum wire hand-wound on a fused silica cross frame in a strain-free design.
• Pressure-sealed glass capsule filled with high-purity helium to preserve integrity and performance.
• Compact dimensions (5.8 mm diameter × 56 mm length) for full immersion in small cells and tight fixtures.

Standards and compliance

• ITS-90 compliant with specified resistance ratios and performance characteristics.
• Engineered and manufactured to serve as a primary standard SPRT for precision temperature-to-resistance conversion.

Designed for demanding measurement environments

• Operates down to 13 K (–260 °C) for cryogenic measurements.
• Glass capsule minimizes heat flow and enhances stability during full immersion.
• Compact, fully immersible probe provides an alternative to long-stem SPRTs for enclosed vessels and constrained setups.
• Each thermometer is annealed and tested for reproducibility, reliability and long-term stability.

Specifications (selected)
Temperature range: 5686: –260 °C to 232 °C (13 K to 505 K)
Nominal R_TPW: 25.5 Ω
Resistance ratio: W(302.9146 K) ≥ 1.11807; W(234.3156 K) ≤ 0.844235
Drift rate: 5686: < 0.005 °C per year over the entire range
Self-heating at TPW: < 0.002 °C under 1 mA current
Reproducibility: ±0.001 °C or better
R TPW drift after thermal cycling: < 0.001 °C
Filling gas: helium (pressure-sealed capsule)
Lead wires: four platinum wires, 30 mm long
Size: 5.8 mm dia. × 56 mm long

Applications and benefits

• Primary standard for cryogenic and immersion calibrations.
• Delivers high stability and repeatability for laboratory metrology and field calibrations.
• Compact form factor enables use in small-volume cells and specialized fixtures.

Technical specifications

• Model: 5686-B Glass Capsule SPRT
• ITS-90 compliance with specified resistance ratios W(302.9146 K) ≥ 1.11807 and W(234.3156 K) ≤ 0.844235
• Temperature range: –260 °C to 232 °C (13 K to 505 K)
• Nominal resistance at TPW: 25.5 Ω
• Drift rate: < 0.005 °C per year (entire range)
• Self-heating at TPW: < 0.002 °C under 1 mA
• Reproducibility: ±0.001 °C or better
• R TPW drift after thermal cycling: < 0.001 °C
• Filling gas: helium (pressure-sealed capsule)
• Lead wires: four platinum wires, 30 mm long
• Probe size: 5.8 mm diameter × 56 mm length