The change in electrical resistance of a platinum sensing element is precisely defined by the temperature; as a result, this relationship can be utilized for thermometry.
The relationship is listed in the table of basic values for Pt 100 (TC = 3850 ppm/K).

Some of the parameters that influence platinum thin-film sensors over their service life are as follows:

Measurement currents and self-heating
The supply current heats the platinum thin-film sensor.
The resulting temperature measuring error is defined by: ΔT = P*S
where P, the power loss = I²R and S, the self-heating coefficient in K/mW.

The self-heating coefficients are specified in the data sheets for the individual products.
Self-heating is dependent on thermal contact between the platinum thin-film sensor and the surrounding medium.
If the heat transfer to the environment is efficient, higher measurement currents can be used.
Platinum thin-film sensors have no low limits for measurement current.
The optimal measurement current is greatly dependent upon the specific parameters of the application.

General recommendations for test current:
– 100 Ω: 0.3 to max. 1.0 mA
– 500 Ω: 0.1 to max. 0.7 mA
– 1000 Ω: 0.1 to max. 0.3 mA
– 2000 Ω: 0.1 to max. 0.3 mA
– 10000 Ω: 0.1 to max. 0.25 mA

For additional tables for 500 Ω and 1000 Ω elements, please visit www.heraeus-nexensos.com

Accuracy tolerance classification
Heraeus Nexensos supplies platinum thin-film sensors in accordance with DIN EN 60751 in the accuracy tolerance classifications F 0.60, F 0.30, F 0.15 and F 0.10 (see table below for limit variations for 100 Ω platinum sensors).
Proportially limited tolerances are based on:

Maximum precision, long-term stability and high resistance make platinum thin-film temperature sensors the sensor of choice in a wide variety of technology sectors.

Driven by our own stimulus for innovation, and motivated by the high demands of our customers, we work constantly further develop and innovate our platinum thin-film technology.
The result is a large product portfolio of platinum temperature sensors for measuring temperatures from -196 °C to +1000 °C with standard resistance values from 100 to 10000 Ω.

The ability to meet high standards and quality demands require the best raw materials, high manufacturing precision and exclusive sensor know-how. This expertise produces sensors that make accurate measurements on a day-to-day basis, millions of times.
Excellent chemical and mechanical stability, resistance to moisture, air and other environmental factors result in measurements reproducible and reliable over thousands of cycles.

Our demanding customers apply these advantages by using our sensors to advance the state-of-the-art of their own products.
We, as an experienced development partner, are the first port of call for our customers worldwide.