Passive electrical network

Hagood, N.W. von Flotow, A. Damping of Structural Vibrations mth Piezoelectric Materials and Passive Electrical Networks. J. Sound and Vibration 146 (2) (1991), pp. 243-268... 

Conventional two-terminal resistors, capacitors, and inductors are passive elements. It follows that networks formed of interconnected two-terminal resistors, capacitors, and inductors are passive networks. Two-terminal voltage and current sources generally behave as active elements. However, when more than one source of externally applied energy is present in an electrical network, it is possible for one or more of these sources to behave as passive structures. Comments similar to those made in conjunction with two-terminal voltage and current sources apply equally well to each of the four possible dependent generators. Accordingly, multiterminal configurations, whose models exploit dependent sources, can behave as either passive or active networks. 

Passive filter An electrical network comprised entirely of passive elements and designed specifically to... 

Let us consider again a sorption system consisting on a sorbent-sorbate phase and a sorptive gas located between the plates or cylinders of a capacitor, Fig. 6.8. This system is an electric network which for small applied voltages (U(t)) can be interpreted as a Linear Passive System (LPS). That is a stimulus (U(t)) applied to the system creates a response, the electric current I(t), which is linearly related to U(t). However it may exhibit a phase shift and also lead to energy dissipation, i. e. Ohmian heat which, as a consequence of the Second Law of Thermodynamics at finite ambient temperature, never can completely be reverted again to electric energy. Linear Passive Systems can be found quite frequently in Physics. A mathematical theory of such systems has been developed by H. Kdnig and J. Meixner in the 1960 s, [6.27] and later on extended and applied to various stochastic processes, i. e. statistical physics by J. U. Keller, [6.28]. 

The Monte Carlo-type electrode model is also called the particle connectivity model because its physics is straightforwardly based on KirchhofTs law for an electrical network, with particle resistance and interconnection resistances defined by a set of rules to mimic the current flow and electrochemical current generation within the microstructure. The electrochemical process is considered to take place with a constant resistance in agreement with intuitive notions about the mechanism. Variants of this concept attach correlated values to the resistances in the network to model polarisation more closely according to a percolation concept of active sites and passive connections [59]. Other specialised types of electrode models are mentioned briefly below,... 

Immittance — In alternating current (AC) measurements, the term immittance denotes the electric -> impedance and/or the electric admittance of any network of passive and active elements such as the resistors, capacitors, inductors, constant phase elements, transistors, etc. In electrochemical impedance spectroscopy, which utilizes equivalent electrical circuits to simulate the frequency dependence of a given elec-trodic process or electrical double-layer charging, the immittance analysis is applied. 

The remarkable resistance of the SC intercellular lipid network to the passive penetration of therapeutic agents has intensified the search for devices, chemical and physical, with the ability to perturb this lipid environment. Of the many physical techniques investigated, iontophoresis (or electrically enhanced transdermal transport) has become an important focal point [160-162]. Unparalleled in its ability to deliver (noninvasively) ionized drugs across the skin, its modus operandi appears to be largely dependent on transcutaneous ion-conducting pathways (which may be paracellular), rather than a function of direct interaction with the lipid infrastructure [163]. Nevertheless, the effect of the applied current on the lipid (and protein) domains is a matter of interest with respect to both safety considerations (i.e., does the applied current induce stmctural alterations ) and mechanistic insight. ATR-FTIR has been used in a number of studies to discern the effect of iontophoresis on SC lipid and protein structures, both in vivo and in vitro. In separate studies, human SC was examined in vivo following the delivery of current at 0.1-0.2 mA/cm for 30... 

There are two types of hubs active and passive. Passive hubs simply connect all ports together electrically and are usually not powered. Active hubs use electronics to amplify and clean up the signal before it is broadcast to the other ports. In the category of active hubs, there is also a class called intelligent hubs, which are hubs that can be remotely managed on the network. 

Due to passive operation of the quartz crystal it is possible to minimize parasitic influences from the experimental setup, i.e., to almost ehminate their effects by calibration. If the interface behaves like a hnear network, most electrical parameters relevant for the measurement can be imphcitly obtained and the influence of the network can be eliminated. Calibration of the measurement setup is one of the important advantages of network analysis and must be performed with care. 

An electrical element or network is said to be passive if the power delivered to it, defined in accordance with Eq. (2.14), is nonnegative. This definition exploits the requirement that the terminal voltage v(t) and the element current i t) appearing in Eq. (2.14) be in associated reference polarity. In contrast, an element or network to which the delivered power is negative is said to be active that is, an active element or network generates power instead of dissipating it. 

MEAs with a catalyzed active area of varying fractions of the total flow field area. In the second approach, the authors used a number of "subcells" at various locations along the gas flow channel that were electrically insulated from the main active MEA and controlled by a separate load. In the third approach, a network of passive graphite resistors were placed between the flow field plate and the current collecting bus plate, while the potential drop across these resistors was monitored to establish the current flowing through them. However, none of these methods provided sufficient spatial resolution, and all involved significant errors due to lateral currents and/or contact resistance. 

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