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A chemical sensor array is a sensor architecture with multiple sensor components that create a pattern for analyte detection from the additive responses of individual sensor components. There exist several types of chemical sensor arrays including electronic, optical, acoustic wave, and potentiometric devices.
A change in length will affect both the spacing between the interdigitated electrodes---altering the pitch---and the spacing between IDTs---altering the delay. This can be sensed as a phase-shift, frequency-shift, or time-delay in the output electrical signal. The fundamental measurement of a surface acoustic wave sensor is typically strain.
A piezoelectric sensor is a device that uses the piezoelectric effect to measure changes in pressure, acceleration, temperature, strain, or force by converting them to an electrical charge. The prefix piezo- is Greek for 'press' or 'squeeze'.
Some sensors require external voltage or current source of excitation, These sensors are called active sensors. (E.g. a temperature sensor like a thermistor & RTD, a pressure sensor (piezo-resistive and capacitive), etc.). The stability and precision of the excitation signal directly relates to the sensor accuracy and stability.
Four-point measurement of resistance between voltage sense connections 2 and 3. Current is supplied via force connections 1 and 4. In electrical engineering, four-terminal sensing (4T sensing), 4-wire sensing, or 4-point probes method is an electrical impedance measuring technique that uses separate pairs of current-carrying and voltage-sensing electrodes to make more accurate measurements ...
However, if voltage at each output terminal is measured with respect to ground, a non-zero voltage will appear. This is the common mode voltage (CMV), and is the same at each output terminal. The output interface then converts the electrical signal from the Hall sensor; the Hall voltage: a signal that is significant to the application context.
They are normally supplied as a polymer sheet or ink that can be applied by screen printing. The sensing film consists of electrically conducting and non-conducting particles suspended in a matrix. The particles are sub-micrometre sizes formulated to reduce temperature dependence, improve mechanical properties and increase surface durability.
There are several retinomorphic sensor designs which yield a similar response. The first designs employed a differential amplifier which compared the input signal from of a conventional sensor (e.g. a phototransistor) to a filtered version of the output, [6] resulting in a gradual decay if the input was constant. Since the 1980's these sensors ...