Primary Standards

Primary Standards

SPRTs 

Model 

RTPW 

Range 

5681 

25.5 W 

–200 °C to 670 °C 

5683 

25.5 W 

–200 °C to 480 °C 

5684 

0.25 W 

0 °C to 1070 °C 

5685 

2.5 W 

0 °C to 1070 °C 

5698 

25.5 W 

–200 °C to 670 °C 

5699 

25.5 W 

–200 °C to 670 °C 

5686 

25.5 W 

–260 °C to 232 °C 

 

Fixed-point cells 

Model 

Description 

Temperature 

5901A-G 

TPW Cell, 12 mm ID with handle, glass shell 

0.01 °C 

5901A-Q 

TPW Cell, 12 mm ID with handle, quartz shell 

0.01 °C 

5901C-G 

TPW Cell, 13.6 mm ID with handle, glass shell 

0.01 °C 

5901C-Q 

TPW Cell, 13.6 mm ID with handle, quartz shell 

0.01 °C 

5901D-G 

TPW Cell, 12 mm ID, glass shell 

0.01 °C 

5901D-Q 

TPW Cell, 12 mm ID, quartz shell 

0.01 °C 

5901B-G 

TPW Cell, mini, glass shell 

0.01 °C 

5900 

TP Mercury, SST 

–38.8344 °C 

5904 

Freezing Point of Indium 

156.5985 °C 

5905 

Freezing Point of Tin 

231.928 °C 

5906 

Freezing Point of Zinc 

419.527 °C 

5907 

Freezing Point of Aluminum 

660.323 °C 

5908 

Freezing Point of Silver 

961.78 °C 

5909 

Freezing Point of Copper 

1084.62 °C 

5924 

Open Freezing Point of Indium 

156.5985 °C 

5925 

Open Freezing Point of Tin 

231.928 °C 

5926 

Open Freezing Point of Zinc 

419.527 °C 

5927A 

Open Freezing Point of Aluminum 

660.323 °C 

5928 

Open Freezing Point of Silver 

961.78 °C 

5929 

Open Freezing Point of Copper 

1084.62 °C 

5943 

Melting Point of Gallium, SST 

29.7646 °C 

5901B 

Mini Triple Point of Water 

0.01 °C 

5914A 

Mini Freezing Point of Indium 

156.5985 °C 

5915A 

Mini Freezing Point of Tin 

231.928 °C 

5916A 

Mini Freezing Point of Zinc 

419.527 °C 

5917A 

Mini Freezing Point of Aluminum 

660.323 °C 

5918A 

Mini Freezing Point of Silver 

961.78 °C 

5919A 

Mini Freezing Point of Copper 

1084.62 °C 

5944 

Mini Freezing Point of Indium, Metal Cased

156.5985 °C 

5945 

Mini Freezing Point of Tin, Metal Cased 

231.928 °C 

5946 

Mini Freezing Point of Zinc, Metal Cased 

419.527 °C 

5947 Mini Freezing Point of Aluminum, Metal Cased 660.323 °C

 

Apparatus 

Model 

Features/Use 

7012 

Maintains: triple point of water and gallium cells.
Comparisons: –10 °C to 110 °C. 

7037 

Maintains: triple point of water and gallium cells.
Comparisons: –40 °C to 110 °C. 

7312 

Maintains: two TPW cells. Compact size, runs quietly.
Comparisons: –5 °C to 110 °C. 

7341 

Maintains: triple point of mercury cell.
Comparisons: –45 °C to 150 °C. 

9210 

Maintains: mini triple point of water and mini gallium cells.  
Comparisons: –10 °C to 125 °C. 

9230 

Maintains: stainless steel gallium cell.
Comparisons: 15 °C to 35 °C. 

9260 

Maintains: indium, tin, zinc, and aluminum cells.
Comparisons: 50 °C to 680 °C. 

9114 

Maintains: indium, tin, zinc, and aluminum cells.
Comparisons: 100 °C to 680 °C. 

9115 

Maintains: aluminum and silver cells.
Comparisons: 550 °C to 1000 °C. 

9116 

Maintains: aluminum, silver, gold, and copper cells.
Comparisons: 400 °C to 1100 °C. 

9117 

Anneals SPRTs, HTPRTs, and thermocouples to 1100 °C.
Protects them against contamination from metal ions. 

Boiling point of liquid nitrogen 

7196 

Affordable substitute for a triple point of argon system. Provides for low-temperature comparison calibrations at approximately –196 °C with uncertainties of 2 mK. 

Resistance bridge 

5581 

0.1 ppm accuracy for calibration of standard resistors and SPRTs. 13:1 measurement ratio allows resolution
to 0.001 mK. 

1590 

1 ppm accuracy for calibration of SPRTs and thermistors. 

Standard resistors 

742A 

Excellent performance without oil or air baths. Values from 10 ohm to 100 megohm. 

5430 

Highest stability oil-filled resistors (< 2 ppm/year drift). AC cal uncertainty to 3 ppm.