Category: Transducers and Sensors.

Initial Balancing

The tolerance of the four bridge components may be such that there is a non-zero offset output voltage. This offset…

Josephson Junctions and SQUID

device has enough energy to multiply by exciting numerous other electrons from the valence to the conduction band of the…

Passive sensors

These include: Variable resistance transducers: The change in resistance of an element can be readily measured. Various components exist whose resistance…

Active sensors

Photovoltaic transducers: e.g. solar cells, portable exposure meters.  Piezoelectric transducers generate electric polarisation, which is linearly related to the applied…

Electrical modelling: Active and passive sensors

Our approach to instrumentation is to treat sensors as circuit elements. We will call a sensor passive when it requires…

Dynamic Range

 The ratio between the maximum and minimum signals the transducer may handle. The maximum is usually limited by compression or…

Some more sensor characteristics

Cross-Talk or Cross-sensitivity Resolution

Memory effects

Linear sensors –Laplace transforms and Convolution Non-linear sensors – Volterra integrals Hysteresis The existence of non-vanishing Volterra kernels gives rise…

Non-linearity

Sensitivity

Threshold and detectivity No sensor will respond to arbitrarily small signals. Signals in the range between zero and the sensor…

Transducers and Sensors

By the end of this section you should be able to: • Discuss the definitions/specifications by which sensors are characterised.…

Bridge Measurement

The sensitivity of a sensor can be increased by incorporating it in a bridge arrangement. Impedance varying sensors are often…