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Model 935-14-77 Standard Platinum Resistance Thermometer. Temperature range -50°C to 670°C.
Model 935-14-77 SPRT, is the metallic sheathed version of the Model 909, the workhorse of calibration
laboratories all over the world.
The resistance element is of pure platinum, coiled and mounted in a strain free construction.
The former is of pure alumina material and all parts have been pre-aged to eliminate contamination and

Standard PRT Thermometer.

Model  Description 
935-14-77 SPRT Thermometer Range -200 to +670°C
All joints are welded to minimize resistance changes. The leads are brought to a handle assembly where
they are connected to a low loss cable, 6 feet long and screened.
The thermometer sheath is of metallic material which is filled with dry air during construction.
It is available in a standard length of 450mm.
The model 935-14-77 is supplied with a calibration certificate giving RTPW and Wga, plus a
comprehensive handbook.
For transportation and storage the SPRT is supplied in its own attractive carrying case.
Please Note: The incanol sheath ensures that the 935-14-77 will not break.
However, internally it has the same construction as a standard platinum resistance thermometer
and must be handled accordingly.
Standard PRT
Model 935-14-77
Measuring Range  -50°C to 670°C
Nominal Resistance  25.5Ω at 0°C
Maximum Current 
Nominal Sensitivity 0.1Ω/°C
Resistance Ratio  Wga ≥ 1.11807 as required by ITS-90
Self-Heating  1mK/25 microwatts
Sealed-In Gas  Dry air 
Stability  Depends upon the temperature range of use.
Typical annual stability, see table above 
Internal Leads  4 wire-platinum 
External Leads  Silver-plated multistrand wires in a
low-loss insulation cable terminating
in gold-plated terminals. 
Length  450mm 
Nominal Diameter  6mm