Discrete electronic components

Following the invention of the transistor, for many years, they were made as individual, discrete electronic components and were connected to other electronic components (resistors, capacitors, inductors, diodes, etc.) on printed circuit boards to make an electronic circuit. The transistor s small size and low power consumption made it an ideal candidate to replace the bulky vacuum tubes then used to amplify electrical signals and switch electrical currents. These beneficial attributes of transistors made it possible for them to be used in making ever more complex electronic circuits in place of vacuum tubes. However, it did not take long before the limits of this approach of building circuits were reached. Circuits... 

Specific information on aging and failure modes of discrete electronic components, or specific instrumentation, is beyond the scope of this book. Aging issues for specific instrumentation should ideally be addressed within each operator s performance standards and maintenance plans, using information acquired from manufacturers, from open literature, from plant experience, or from other sources. 

The machine controls tested in BIA up to new were equipped with hardware ccirparators in positive contact action technique relays or with discrete electronic components. 

Simple fcd.lsafe comparator circuits consisting of a few discrete electronic components only, are listed in the references /5, 6/. Fig. 7 shows a failsafe comparator for antivalenoe according to the principle of the circuit system described in /6/. Only if the signals A 1 and A 2 show antivalent potentials to each other the bridge-connected rectifier is able to amplify the test clock at its basis. 

The electronic functions required for single detector assemblies are generally common to all detectors bias (usually adjustable), amplification, output offset, and, perhaps, some specialized postprocessing. Some of these functions are unique to single detector assemblies only because they may be built of discrete electronic components (as opposed to incorporation in an ROIC as is done for FPAs), or the postprocessing may be provided in an analog way (as opposed to the software-controlled postprocessing usually done with FPAs). 

Frequency filtering for noise reduction - for single detector assemblies, this may be done with discrete electronic components in an op-amp amplifier (tfan-simpedance amplifier, or TIA). 

Figure Bl.6.11 Electron transmission spectrum of 1,3-cyclohexadiene presented as the derivative of transmitted electron current as a fiinction of the incident electron energy [17]. The prominent resonances correspond to electron capture into the two unoccupied, antibonding a -orbitals. The negative ion state is sufficiently long lived that discrete vibronic components can be resolved.

Alkaline-Earth Titanates. Some physical properties of representative alkaline-earth titanates ate Hsted in Table 15. The most important apphcations of these titanates are in the manufacture of electronic components (109). The most important member of the class is barium titanate, BaTi03, which owes its significance to its exceptionally high dielectric constant and its piezoelectric and ferroelectric properties. Further, because barium titanate easily forms solid solutions with strontium titanate, lead titanate, zirconium oxide, and tin oxide, the electrical properties can be modified within wide limits. Barium titanate may be made by, eg, cocalcination of barium carbonate and titanium dioxide at ca 1200°C. With the exception of Ba2Ti04, barium orthotitanate, titanates do not contain discrete TiO ions but ate mixed oxides. Ba2Ti04 has the P-K SO stmcture in which distorted tetrahedral TiO ions occur. 

Nonelectronic Parts Reliability Data I99P (NPRD-91) and Eailure Mode/Mechanism Distributions 1991 s (fMD-91) provide failure rate data for a wide variety of component (part) types, including mechanical, electromechanical, and discrete electronic parts and assemblies. They provide summary failure rates for numerous part categories by quality level and environment. 

Intercormection and packaging allow electronic devices to be usefully incorporated into products. The manufactrrre of complex electronic systems reqtrires that htmdreds of thousands of electronic components be efficiently cormected with one another in an extremely small space. In the past, this was accomplished by hand wiring discrete components on a chassis... 

The components of the discrete electronics can be easily integrated into the control unit of the washing machine. This enables the user to define layout and performance of the electronics. 

Electron-transfer proteins have a mechanism that is quite different from the conduction of electrons through a metal electrode or wire. Whereas the metal uses a continuous conduction band for transferring electrons to the centre of catalysis, proteins employ a series of discrete electron-transferring centres, separated by distances of I.0-I.5nm. It has been shown that electrons can transfer rapidly over such distances from one centre to another, within proteins (Page et al. 1999). This is sometimes described as quantum-mechanical tunnelling, a process that depends on the overlap of wave functions for the two centres. Because electrons can tunnel out of proteins over these distances, a fairly thick insulating layer of protein is required, to prevent unwanted reduction of other cellular components. This is apparently the reason that the active sites of the hydrogenases are hidden away from the surface. 

Until the past decade, the cytoplasm was widely considered to be structurally unorganized with the main division of labor at the organellar level. Certainly, relatively little was known about the nature of the cyto-skeleton (with the notable exception of the mitotic apparatus and striated muscle), and the dynamics of cytoplasmic behavior were conceptualized vaguely in terms of sol-gel transitions without a sound molecular foundation. Substantial improvements in electron, light, and fluorescence microscopy, as well as the isolation of discrete protein components of the cytoskeleton, have led the way to a much better appreciation of the structural organization of the cytoplasm. Indeed, the lacelike network of thin filaments, intermediate filaments, and microtubules in nonmuscle cells is as familiar today as the organelles identified... 

In three dimensions a spatial wave group moves around an harmonic ellipsoid and remains compact, in contrast to the dispersive wave packets of classical optics. The distinction is ascribed to the fact that the quantum wave packet is built up from discrete harmonic components, rather than a continuum of waves. The wave mechanics of a hydrogen electron is conjectured to produce wave packets of the same kind. At small quantum numbers the wave spreads around the nucleus and becomes more particle-like, at high quantum numbers, as it approaches the ionization limit where the electron is ejected from the atom. 

We have previously presented results of calculations showing that polymer nanoparticles with excess electrons exhibit discrete electronic structure and chemical potential in close analog with semi-conductor quantum dots. The dynamics of the formation of polymer nanoparticles can be simulated by the use of molecular dynamics and the morphology of these particles may be predicted. The production method that is used for the creation of these polymer particles can also be used to mix polymer components into a nanoparticle when otherwise they are immiscible in the bulk Quantum drops, unlike the semiconductor quantum dots, can be generated on demand and obtained in the gas phase. In the gas phase, these new polymer nanoparticles have the capacity to be used for catalytic purposes which may involve the deUveiy of electrons with chosen chemical potential. Finally, quantum drops have unusual properties in magnetic and electric fields, which make them suitable for use in applications ranging from catalysis to quantum computation. 

Biosensors provide a powerful and inexpensive alternative to conventional analytical strategies for assaying chemical species in complex matrices. A biosensing device incorporates a biological molecular recognition component connected to a transducer. The main aim of a transducer is to produce a continuous or discrete electronic signal, which is directly proportional to the concentration of an analyte. In biosensors, the following sequence of events take place ... 

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