Sensor body

The sensor body consists of a coil with two connections and an electrode with a tapping point. An aluminium measuring ring is attached to the object to be measured. The measurement is based on the eddy - current principle. The non-con-ductive layer between the core and the coil produces a capacitive circuit. The output signal is related to the position of the target. 

Sensor body Signal converter (ceramic) j + amplifier... 

Body movement, posture Piezoresistive strain/ pressure sensors, accelerometers, gyroscopes, optical fibre sensors Body kinematics Dependent on motion to be analysed... 

Mitchell, E., Coyle, S., Ward, T., O Connor, N.E., Diamond, D., 2010. Breathing Feedback System with Wearable Textile Sensors. Body Sensor Networks (BSN 2010), Biopolis, 7—9 June, Singapore. 

Clark-type electrodes show a linear response over almost four orders of magnitude. The upper limit is determined by the saturation of the sample with dissolved oxygen ( 10 mg 1 in water at atmospheric pressure) while the lower limit is caused by the so-called residual current. This is due to impurities that can be reduced on the cathode, as well as trace oxygen present in the electrolyte solution or gassing out from the solid materials comprising the sensor body. A typical detection limit is 0.05 mg 1 of dissolved oxygen. 

If the sensor bore does not correspond to the required tolerances, the sensor front touches the sensor bore in many cases, and the sensor loses its sensitivity. In technical language, this effect is called force shunt and can cause measurement errors of up to 30%. For this reason, cavity pressure sensors have recently developed that are initially built precisely into a sleeve and then calibrated in a second step [1]. The actual sensor is thus protected during installation, and measurement errors through the installation are excluded (PRIASAFE principle). The determined sensitivity is eventually stored in the sensor body itself as a code, so that no adjustments in the subsequent electronics in the industrial use have to be made [2]. The optimal measuring ranges are determined automatically as soon as the sensor is connected to the electronics (PRIASED principle). 

Depending on requirement, today, cavity pressure sensors are available with different dimensions, where not only the diameter of the sensor front but also the size of the sensor body plays an important role during the installation. Basically, the size of cavity pressure sensors should only be chosen as small as necessary, both to keep the installation costs to a minimum and to keep the required tolerances as simple as possible. 

One of the merits of an enzyme biosensor is its versatility. The selectivity of biosensors directly relates to the type of enzyme used for constructing biosensors. Up to now, many kinds of enzyme sensors have been reported, other lhan glucose biosensors, using a variety of enzymes. A miniaturization of the sensor body is another possible advantage of enzyme sensors. In fact, miniature sensors sized in microns have been prepared... 

According to another procedure, a drop of the urease-buffer mixture (pH 7.0) is placed on the outer surface of an NH3 sensor gas-permeable membrane, covered with a suitable cellulose membrane, and incorporated into the sensor body according to the instructions of the manufacturer [183]. Even though the pH value is such that NHj ions predominate, the sensor still shows a Nernstian response to the urea concentration. Even full blood analyses are possible. 

In a similar mechanism of signal transduction, one can use a pH-sensitive field-effect transistor (FET) for developing enzyme-modified FETs. The use of a FET provides superiority in miniaturization of the sensor body because a FET is usually produced through mass production on semiconductor materials. 

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