Applications electromagnetic interference

Sn02 and indium tin oxide (ITO) for conductive transparent coatings on glass for electromagnetic interference (EMI) applications. 

The BioView sensor (DELTA Light Optics, Denmark) was developed especially for industrial applications. It is capable of completely automatic optical measurement for monitoring and control of different bioprocesses. The instrument is conceived to withstand harsh industrial environments (e.g., high temperature, moisture) and electromagnetic interference. For data transfer a single-fiber asynchronous modem is used, which allows a distance between the computer and spectrometer of up to several hundred meters. 

Electromagnetic interface shielding is the most common application. Conductive fibres braided into a shield or sock offer superior performance against electromagnetic interference, and they present the following advantages ... 

Today fiber-optic transmission systems offer several advantages over conventional copper wire and coaxial cable systems. Among these are increased bandwidth, smaller size, lower weight, lack of crosstalk, and a very low susceptibility to electromagnetic interference. It is to be expected that these advantages will open widespread application of fiber-optic transmission systems in the future. This seems to be supported by the fact that a great number of public and in-house trial systems are under test all over the world. 

The renewable energy processes will be monitored and controlled by small, fast, and economical detectors, and fiber optics will play a major role in their designs. The operation and applications of fiber-optic probes have already been discussed in connection with Figure 3.2, so only a brief summary is provided here. Fiber-optic probes can be installed in situ, whereas their readout instruments can be several hundred meters from the probe. The probe can be located in toxic, corrosive, radioactive, explosive, high- or low-temperature/ pressure, and noisy environments. Because the measurement signal is optical, the cables are immune to microwave or electromagnetic interference. 

An important application of ferrites is for shielding sensitive equipment (e.g. data-processing, telecommunications and audio-visual equipment) from electromagnetic interference (EMI). Both NiZn- and MZn-based ferrites components are capable of suppressing interference up to the GHz frequency range by virtue of the high impedance they present to high frequency currents. The ferrite parts are made in a variety of shapes to enclose the leads to be shielded, as shown in Fig. 9.17. 

In view of its application in the field of electronics there is particular interest in the coating of polypropylene mouldings against radio-frequency and electromagnetic interference the successful development of aqueous processes for polycarbonate provides a viable alternative to other methods for shielding the housings of electronic products—such as by paints containing nickel. 

Electrical Conductivity. Unmodified polymeric resins are natural insulators and do not exhibit electrical conductivity. There are certain applications, however, where electrically conductive adhesives provide a significant value. One such application is the use of conductive adhesives as an alternative for wire or circuit board soldering. Another application, with less of a requirement for conductivity, is the assembly of components that are shields or protection from electromagnetic interference. 

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