|
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 strain.
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
quartz material which is filled with dry air during construction.
Three lengths are available, standard length 480mm, extra length 550mm
or maximum length 600mm.
The model 909 is supplied with a calibration certificate giving RTPW and
Wga.
For transportation and storage the Model 909 is supplied in its own
attractive carrying case.
|
| Model |
909-25.5 |
909-100 |
| Measuring Range |
-196°C to 670°C |
-196°C to 550°C |
| Nominal Resistance |
25.5Ω at 0°C |
100Ω |
Recommended
Maximum Current mA |
1 |
0.5 |
Nominal Sensitivity
Ω/°C |
0.1 |
0.4 |
| Resistance Ratio |
Wga > 1.11807 as
required by ITS-90 |
| Self-Heating |
1mK/25 microwatts |
| Sealed-In Gas |
Dry air |
| Internal Leads |
4 wire-platinum |
| External Leads |
Silver-plated
multistrand wires in a
low-loss insulation cable terminating
in gold-plated terminals. |
| Length |
480mm standard
550mm to order (E)
600mm to order (L) |
| Nominal Diameter |
7.5mm |
|
|
|
