P2.8 Simultaneous measurement of resistance and temperature changes in bridge circuits
- 20. GMA/ITG-Fachtagung Sensoren und Messsysteme 2019
2019-06-25 - 2019-06-26
- P2: Messsysteme
- K. Gintner - Hochschule Karlsruhe (Deutschland)
- 708 - 714
Wheatstone Bridge Circuits are commonly used in sensor applications to measure the resistance change of sensor elements, which represent typical metrics such as pressure, force or magnetic flux density. In many applications, for example, magnetoresistive or pressure-sensitive sensor elements are used in Wheatstone bridges. A temperature change of the Wheatstone bridge leads not only to a change of the resistance of the sensor elements, but also of the reference resistors. The reason for this is the (mostly positive) temperature coefficient of the resistors and also the dependence of the sensor effect on the temperature. In order to obtain a more accurate result, the temperature of the bridge circuit should therefore be known. By using several different voltages in a bridge circuit and knowing the temperature coefficients, it is possible to determine the exact resistance change of the sensor elements and the temperature change simultaneously without using an additional temperature sensor. A possible offset of the bridge circuit due to a mismatch of the four resistors is not relevant.