Circuit Capacitors

Fig. 10.5 Schematic illustration of an integrated-circuit capacitor structure.

When a periodically changing excitation signal is chosen for the operation of chemiresistors, they can be used to detect changes of capacitance (Fig. 8.1b). Therefore, the dielectrometric sensors rely on the chemical modulation of one or more equivalent circuit capacitors, either through the change of the dielectric constant of the chemically sensitive layer or through the chemical modulation of the interfacial charge. 

To estimate the temperature evolution of the entire domain structure we express its energy at T = 0 (i.e. at f = —1) in the Kittel approximation, assuming a kink-like structure of the domain wall and a flat profile of a polarization inside domains. The calculations are similar to those for the domain structure of the uniaxial ferroelectric film surrounded by paraelectric dead layers and embedded into short circuited capacitor [27]. The free energy is superimposed from the domain walls energy and electrostatic contributions ... 

With DC electric motors, power factor correction is sometimes used to improve the power factor of the drive [30]. This is done by incorporating capacitive components into the circuit. Capacitors produce leading reactive power whereas the phase-controlled rectifiers produce lagging reactive power. Thus, by adding appropriately sized capacitors, the power factor of the drive can be improved. 

The frequency dependence of the quality factor Qc (this figure of merit usually appHes to capacitors used in tuned circuits) and its maximal value can be found by inverting the DF(ffl) characteristic. The standard measurements of Qc for the tuned circuit capacitors are made at the frequency of 1 MHz. 

IEEE Journal of Solid-State Circuits (capacitor as a component of solid-state electronic circuits). 

The peak current value of the fundamental frequency component in the load, /ad is the coefficient of the fundamental frequency component of the Fourier series of the collector current All harmonic current is shunted to ground by the tank circuit capacitor and assumed to be zero. The tank circuit is resonant at the fundamental frequency. 

As essential elements in electrical circuits, capacitors have been used in the operation of countless systems and devices ranging from high power engines to microcircuits. The two classes of capacitors are (1) Class I linear capacitors and (2) Class II nonlinear capacitors. In this chapter, a concise introduction of the principles and fundamental operations of capacitors from a science... 

It is important to understand why this twofold approach is needed. Prior to the 1980s, system failures could usually be identified as specific component failures (e.g., relay open circuit, capacitor short circuit, motor fails to start). However, since then the growth of complexity (including software) has led to system failures of a more subtle nature whose cause may not be attributable to a catastrophic component failure. Hence we talk of ... 

The purpose of the substrates is to support discrete active components, integrated and passive circuits, capacitors, resistors, varistors, thermistors etc. connected by conducting tracks. The coefficients of expansion of the different materials must be as close as possible in order to avoid the appearance of stresses of thermal origin, susceptible to induce failure of the circuit. Roughness is also an important parameter. It therefore appears that the choice of a material for making a substrate must take into account not only electronic requirements, but also mechanical, thermal and even chemical requirements. 

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