Sensors and Transducers

The terminology used for characterizing the performance of sensors. Discussion of the physical phenomena and devices which can be used for measuring displacement, velocity, acceleration, force, pressure, flow, strain, temperature, radiation and concentrations of chemical species. Identification of sources of uncertainty in measurements, use of simulated data for error analysis, techniques for improving the signal-to-noise ratio.

The student will learn how to select a suitable and affordable sensor for a particular application; how to use resistive sensors (bonded and non-bonded strain gauges), inductive sensors (linear variable differential transformers) capacitive sensors, and fibre optics for the measurement of displacement, stress and vibration; how to use a Wheatstone bridge, modulated excitation, and synchronous demodulation for detecting small signals. The student will also learn to distinguish fluctuations which are inherent to poisson statistics and particle counting (using a Geiger-Mûller counter or a photomultiplier tube) from genuine noise, traceable to other sources, and use this knowledge to distinguish between photon counting and thermal sensing of light. The student will become familiar with the application of optical absorption and emission spectroscopy to chemical sensing (including hygrometry and detection of dioxygen), scintillation counting and detection of pressure through quenching of luminescence by dioxygen.

The basic principles will be explained through lectures and accompanying reading material. Three laboratory exercises, demonstrations of various sensors, and an assignment involving analysis of real and/or simulated data. A re-sit examination may be changed from written to oral.