External inductor

FIGURE 2.104 Typical temperature profile on the cavity surface of an external inductor [10,... 

From this equaiion one can determine the required value of neutral circuit impedance for a particular level of ground fault current. The external impedance will be Z, less the ground impedance. In HT systems one c in also delermine the likely value of a ground inductor coil to achieve a near-resonance condition, to eliminate the arcing grounds, on the one hand, and facilitate a strike-free extinction of an arc hy the interrupting device, on the other. 

The bath is normally at a temperature in the range 620-710°C, depending on whether the coating material is an aluminium-silicon alloy (for use in high-temperature conditions) or pure aluminium (for corrosion prevention). It is heated by inductors, by resistance heaters or by an external flame. The pot will usually be refractory lined unless cast-iron pots are needed to ensure adequate heat transfer from an external flame. As molten aluminium is extremely aggressive towards ferrous metals, replacement of cast-iron pots is fairly frequent. Refractory-lined pots obviously do not have this drawback, although the bath hardware, in particular the sinker roll and support mechanism, will still be attacked and need replacement at intervals. 

To date, direct asymmetric synthesis of optically active chiral-at-metal complexes, which by definition leads to a mixture of enantiomers in unequal amounts thanks to an external chiral auxiUary, has never been achieved. The most studied strategy is currently indirect asymmetric synthesis, which involves (i) the stereoselective formation of the chiral-at-metal complex thanks to a chiral inductor located either on the ligand or on the counterion and then (ii) removal of this internal chiral auxiliary (Fig. 4). Indeed, when the isomerization of the stereogenic metal center is possible in solution, in-... 

IC, and the software tool may not have warned you. You should also observe that such software tools often do not consider important external component tolerances. For example, your inductor itself may have a +20% tolerance on its inductance. But 20% lower inductance could mean up to 25% higher peak currents (if you are operating close to the CCM-DCM boundary, though with an r of 0.4, the increase in the peak would only be 0.2 x 0.25, i.e., 5%). Note that 1/0.8 = 1.25, so if L falls 20%, the AC current increases 25%. 

Blog Entry 3 A more simple solution to implement is to use the 3478 Low-side N-channel controller in a SEPIC configuration. This application utilizes two inductors (instead of a Flyback transformer) to attain the Buck-Boost function. The 3478 requires an external user-selectable Fet switch, so you can choose the one that suits your load current requirement. The datasheet provides an application rationale for SEPIC configuration on page 19, Figure 13. The output voltage can be set to 12V by changing the value of the feedback resistor. 

Passive filter A kind of usually simple filters composed of elements such as resistors (R), capacitors (C), and inductors (L) that do not depend upon an external power supply. There are different passive filters such as the so-called RC, RL, LC, and RLC varieties. Inductors block high-frequency signals and conduct low-frequency signals, while capacitors do the reverse. Resistors have no frequency-selective properties, but are added to inductors and capacitors to determine the time-constant of the circuit. 

Active filter A type of device composed of a combination of passive and active (amplifying) components. Frequently, the latter are transistors or operational amplifiers that require an external power supply to work. Active components commonly have high Q, and achieve resonance without the use of inductors. The Q value (goodness factor) is used to measure the quality of a filter. Thus, a filter has a high Q if it selects or rejects a narrow range of frequencies compared with its center frequency. Other filters that can be included into this class are ... 

In attempting to generally reduce parasitics and their associated losses, we may notice that these are often dependent on various external factors — temperature for one. Some losses increase with temperature — for example the conduction loss in a mosfet. And some may decrease — for example the conduction loss in a bjt (when operated with low currents). Another example of the latter type is the ESR-related loss of a typical aluminum electrolytic capacitor, which also decreases with temperature. On the other hand, some losses may have rather strange shapes. For example, we could have an inverted bell-shaped curve — representing an optimum operating point somewhere between the two extremes. This is what the core loss term of many modern ferrite materials (used for inductor cores) looks like — it is at its minimum at around 80 to 90°C, increasing on either side. 

To minimize this troublesome process, the concentration of the intermediate has to be kept as low as possible by means of catalytic tautomer-ization of the dienol. To make the chiral discrimination as great as possible, a strong interaction between the prochiral intermediate and the chiral environment is needed. When the chiral inductor is introduced into the starting molecule itself, diastereoselective photodeconjugations can be observed. If an external chiral inductor is used, enantioselective protonations are obtained. This approach, which may be catalytic if the chiral auxiliary is not consumed in the process, can take advantage of the acidic property of enols [27] and of the possibility of an acid- or base-catalyzed tautomer-ization of enols [28]. 

With chiral molecules, there is no need for external chiral inductors to induce a diastereoselection. For most esters made from conjugated acids and chiral alcohols, the diastereoisomeric excess (de) of the photodeconjugation process, carried out in apolar solvents containing catalytic quantities of alcohols (and/or amines), remains low. This results from the low steric interactions developed by the alkoxy group during the protonation step of the dienol, as already indicated [32]. However, if protonation of photo-dienols from one enantioface is sterically hindered, as can be observed for isobornyl derivatives 8c and 8d, values of de up to 95% can be attained [50] (Table 4 and Scheme 6). 

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. 

To reduce this problem, most manufacturers add small series resistors and capacitors to ground at the input terminals. Inductors also may be added, but they are susceptible to external magnetic fields. If package shielding is inadequate, the inductors may, in fact, pick up as much noise as they are supposed to filter out. Another RFI defense consists of placing donut-shaped ferrite beads on the input leads of affected stages. 

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