AM1860/1850 SPRTs


  • Metal sheathed
  • Great reference thermometer for dry block calibrators
  • Temperature range: -200 °C to 670 °C


Standard Platinum Resistance Thermometers (SPRTs) are common used to interpolate temperature in the range from -189.3442°C to 660.323°C on the International Temperature Scale of 1990 (ITS-90).  They are widely used as standard or reference thermometers to calibrate other thermometers and to measure temperature precisely in primary and secondary laboratories. AM1850 and AM1860 SPRTs are the crown jewels of AccuMac temperature probes. It takes decades of our scientific expertise and original craftsmanship to create these world class products. They feature a very low drift rate. 
To improve the durability of the SPRT, Inconel 600 replaces quartz glass as sheath material of the thermometer. A special capsule is adopted to protect the platinum sensor wire from contamination introduced by metal sheath at high temperature. All parts used in the thermometer are completely cleaned and treated at high temperature before assembly. The gas mixture filled in the thermometer is well controlled to reduce oxidation effect as low as possible. Every SPRT is fully tested for stability after manufactured. This world class probe meets ITS-90 criteria of standard thermometer fully with a very competitive pricing.
AM1850 has a temperature range from -200°C to 500°C. AM1860 covers range from -200°C to 670°C. They are widely used as reference thermometer at drywell block calibrator and temperature bath.



Temperature Range
1850: -200°C to 500°C
1860: -200°C to 670°C
Nominal 25 Ω or nominal 100 Ω
Resistance Ratio
Drift at 0.01°C*
1850      ΔR(0.01°C ) <0.002 °C/100 hours at 500°C
                ΔR(0.01°C ) <0.008 °C/year
1860      ΔR(0.01°C ) <0.003 °C/100 hours at 670°C
                ΔR(0.01°C ) <0.01 °C/year
±0.0015 °C
Thermal Shock
±0.0015 °C after 10 times thermal cycles from minimum to maximum temperatures
0.0015 °C at 1 mA current
Measurement Current
1 mA
Sensor Length
42 mm
Insulation Resistance
>1000 MΩ at room temperature
Sheath Material
1850: 6.35 mm (OD) X 480 mm (L)
1860: 6.35 mm (OD) X 500 mm (L)
External Leads
Insulated copper wire, 4 leads, 2.5 meters
Gold-plated Spade
Handle Dimension
21mm (OD) X 80 mm (L)
Not included

Optional Accessories

Complementary Wooden Carrying Case

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