Resistance of Pt100 temperature sensorsThe name Pt100 is composed of the chemical symbol for platinum (Pt) and the resistance value of 100 ohms specified at 0°C.
The Pt100 sensor is based on the principle that the electrical resistance of an electrical conductor changes with a change in changes in temperature.
So actually almost all electrically conductive materials can be used.
For practical use in temperature measurement, however, they must meet certain conditions.
Platinum has a high melting temperature and high chemical resistance, which allows precise measurements, with high stability and accuracy, even under adverse conditions.
Like all metals, the Pt100 sensor has a temperature-dependent resistance that increases with rising temperature. (PTC = Positive Temperature Coefficient). A useful change in resistance already occurs at low temperatures.
In addition to metal temperature sensors, sensors made of a wide variety of metal oxides are also used in mass applications. These often provide a usable change in resistance only at higher temperatures.
The resistance decreases when the temperature increases (NTC = Negative Temperature Coefficient).
The advantage of these sensors is the low-cost production and the small design with high response sensitivity.
On the other hand, the lower accuracy, the restricted measuring span, sensor-specific resistance values and a non-linear change in resistance, which make an adaptation of the downstream evaluation electronics necessary.
Resistance values according to DIN EN 60751
Calculating of the Pt100 resistance value
The right window then displays the resistance in ohms calculated for the Pt100 resistance sensor.
Calculation formulas for Pt100 resistorThe resistance of the Pt100 sensor is calculated according to DIN EN 60751 using the following 2 formulas:
- Temperature range: -200 to 0°C:
Rt = R0 * (1 + A * t + B * t2 + C * (t-100) * t3)
- Temperature range: 0 to 850°C:
Rt = R0 * (1 + A * t + B * t2)
R0=Nominal resistance Pt100 at 0°C = 100 Ohm
A= 3,9083 * 10-3
B= -5,775 * 10-7
C= -4,183 * 10-12