Printed circuit boards, advantages

This type of coil was prepared from copper cladded printed circuit board material by applying photolithographic techniques. The p.c. board material is available with difierent copper thicknesses and with either a stiff or a flexible carrier. The flexible material offers the opportunity to adapt the planar coil to a curved three dimensional test object. In our turbine blade application this is a major advantage. The thickness of the copper layer was chosen to be 17 pm The period of the coil was 100 pm The coils were patterned by wet etching, A major advantage of this approach is the parallel processing with narrow tolerances, resulting in many identical Eddy current probes. An example of such a probe is shown in fig. 10. 

Two resin systems based on this chemical concept are commercially available from Shell Chemical Company/Technochemie under the COMPIMIDE trademark COMPIMIDE 183 (34) [98723-11-2], for use in printed circuit boards, and COMPIMIDE 796 [106856-59-1], as a resin for low pressure autoclave mol ding (35). Typical properties of COMPIMIDE 183 glass fabric—PCB laminates are provided in Table 8. COMPIMIDE 183 offers a combination of advantageous properties, such as a high glass transition temperature, low expansion coefficient, and flame resistance without bromine compound additives. 

Industrial applications of PEEK take advantage of the outstanding thermal properties, and include use in high-performance automotive and aerospace components, and in printed circuit boards. 

In addition to suitability to cheap mass production, piezoelectric transformers offer the advantage of a low profile when mounted on printed circuit boards. Over recent years they have found a commercially significant application for powering fluorescent lamps for back-lighting the screen in lap-top computers and electronic notebooks with liquid crystal displays. For these applications the output voltage and power are typically approximately 1 kV (rms) and 5 W, respectively. 

Meanwhile, the price of transistors had fallen sharply as they started to become more widely used in domestic applications, and this, coupled with the desire to produce more sophisticated instruments, led instrument manufacturers to start incorporating them into their new products. The principle advantage in doing this was that the new circuits could be built on a modular basis using printed circuit boards, allowing considerable savings in production costs and at the same... 

A model has been developed for the prediction of the lay-up consolidation process during the lamination of prepreg lay-ups for the manufacture of printed circuit boards. This model can be used advantageously in prepreg material screening and in the optimization of lamination schedules for high-performance structural composites. 

Even after production of printed circuit boards and semiconductor components, ion chromatography may be taken advantage of. Malfunctions are often caused by corrosive anions on the surface of printed circuits or inside, where the microchips are imbedded. Identification and quantification of these compounds with the aid of ion chromatographic techniques often represents a significant contribution for localizing the sources... 

Flip chip technology is a simple idea of flipping a chip to connect its device I/Os downside directly on the printed circuit boards. The apparent advantages are shorter electron pathways, increased number of I/Os per unit area for increased speed and power, cost reduction, and increased package density [1],... 

When combined with complementary measurements, such as locally resolved current measurements, the information value of neutron radiographic measurements can be further enriched. Taking advantage of the penetration power of neutrons, a dedicated cell design including a multi-layer printed circuit board with an embedded matrix of shunt resistors was used to measure the local current densities and the liquid water distributions concurrently [24]. With the combination of these methods, it is possible to correlate the local water content with the local electric performance of the cell. Figure 18.14 shows the superposition of the... 

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