Experimental and Theoretical Evaluation of the Achievable Accuracies of Resonating Viscosity and Mass Density Sensors

Electrodynamically driven resonators upon immer- sion in a sample liquid which can be used as viscosity and mass density sensors are presented. The most promising concepts for such resonant sensors include devices which are fabricated in technologies involving clamped wire and plate structures. In this contribution, achievable accuracies for these types of resonating sensors are considered and investigated by means of long term measurement series. As a suitable reference for such devices, a steel tuning fork is used, which serves as a frequency standard in low frequency applications (440 Hz). Such tuning forks can serve as viscosity and density sensors themselves if they are immersed in a liquid. In order to make their frequency response electronically accessible, an electromagnetic driving and readout setup has been devised to compare their performance to the wire- and plate-based sensors.