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A current feedback amplifier (CFA) has good high-speed properties but its performance is very dependent on interconnect designs, particularly its feedback interconnect design. In this brief, effects of the location of a feedback resistor in the feedback interconnect design of a CFA are analyzed in the frequency domain. A transfer function of a CFA is derived, and frequency responses are simulated by varying the location of a feedback resistor in the transfer function. Then, experiments are carried out with test circuits consisting of CFAs with diverse locations. It can be seen that further distance of the resistor to the inverting input of the CFA results in larger distortion of the CFA's frequency response. This result is true even if the total length of the feedback interconnect is constant. Index Terms--Current feedback amplifier (CFA), feedback interconnect, feedback resistor, frequency-domain analysis.

This paper analyzes the effect of the coordination of optimal reclosing and fuzzy logic-controlled braking resistor on the transient stability of a multimachine power system in case of an unsuccessful reclosing of circuit breakers. The transient stability performance of the coordinated operation of optimal reclosing and fuzzy controlled braking resistor is compared to that of the coordinated operation of conventional auto-reclosing and fuzzy controlled braking resistor. The effectiveness of the proposed method is confirmed by simulations in case of a nine-bus power system model as well as a ten-machine system. Simulation results of both balanced and unbalanced faults at different points in the power systems show that the coordinated operation of optimal reclosing and fuzzy controlled braking resistor is able to stabilize the systems well in case of an unsuccessful reclosing. Moreover, the transient stability performance of the coordinated operation of optimal reclosing and fuzzy controlled braking resistor is better than that of the coordinated operation of conventional auto-reclosing and fuzzy controlled braking resistor. Index Terms--Balanced fault, braking resistor (BR), fuzzy controller, global positioning system (GPS), optimal reclosing, power system transient stability, unbalanced faults, unsuccessful reclosing.

In this paper, premature damage to some static inverter loading resistor modules is analyzed. Furthermore, investigations were carried out to determine the origins and causes of this serious damage occurring on the resistor modules in service. Investigations were preformed on the insulating liquid samples as well as new resistor modules. From the results obtained, it seems that the origin of the damage is from a long-standing, free-burning arc between two resistor windings, following mechanical breakdown. Index Terms--Dielectric liquids, electric breakdown, arc heating, bubbles, fault diagnostic.

In this paper, a supervisory two-layer control structure is synthesized with network elements as control means for thyristor-controlled braking resistor (BR) of multimachine power system operating in transient emergency state. This creates a nmltiple local feedback controller that can be realistically implemented using only local measurements and whose performance is consistent with respect to changes in network configuration, loading, and power transfer conditions. Following a major disturbance, the rotor angle and rotor speed of each generator unit are determined and the firing angle of the thyristor switch associated with the BR is computed by the local controllers. By controlling the firing angle of the thyristor, the BR controls the accelerating power in each generator and, thus, enhances the stability margins and damping oscillations. Since the local controllers rely only on measurements particular to their own subsystem, interconnection effects and the nonlinearities introduced by them are accounted for by the supervisory layer. The two-layer controller was tested on the IEEE Western States Coordinating Council (WSCC) test system. Results show that the controller is capable of bringing the system under control when starting with inherently unstable conditions, even when the severity of the disturbances is increased. Index Terms--Braking resistor (BR), firing angle, hierarchical structure, optimal control, thyristor switch, transient stability crisis.

Some resistive (more generally, algebraic, e.g., dc magnetic or dielectric) 1-ports, composed of elements having a single-degree characteristic (f(x) ~ [x.sup.a]) are considered and some general relations relevant to such 1-ports of an arbitrary structure are proved. For series-parallel (s-p) 1-ports and also fractal 1-ports, this specific characteristic permits constructive (formulas) circuit solution. A generalization of the concept of conductivity is thus obtained. Index Terms--Circuit analysis, power-law characteristics, resistive (algebraic) one-ports.

Arbitrary interconnections of passive (possibly nonlinear) resistors, inductors, and capacitors define passive systems, with power port variables the external source voltages and currents, and storage function the total stored energy. In this paper, we identify a class of RLC circuits (with convex energy function and weak electromagnetic coupling), for which it is possible to 'add a differentiation' to the port terminals preserving passivity--with a new storage function that is directly related to the circuit power. To establish our results, we exploit the geometric property that voltages and currents in RLC circuits live in orthogonal spaces, i.e., Tellegen's theorem, and heavily rely on the seminal paper of Brayton and Moser published in the early sixties. Index Terms--Brayton-Moser equations, nonlinear circuits, passivity, Tellegen's theorem.

Temperature-dependent characteristics of polysilicon and diffused resistors are examined and reported.

The effect of a current-sensing resistor used in current-mode control of pulsewidth modulator (PWM) converters on required MOSFET aspect ratio, the ratio of channel width to channel length generally known as W/L, is studied. The results can also be applied to the effect of source parasitic resistance in a power MOSFET. These resistances require a significant increase in aspect ratio to achieve a desired maximum current capability. Experimental results are presented verifying the validity of the theoretical results. Index Terms--Current-mode control, current-sensing resistor, power MOSFET aspect ratio, power MOSFET model, pulsewidth modulated (PWM) converters.

A procedure for implementing a ballast resistor is described. The extended ledge is used as a ballast resistor and for passivation.

Heterogeneity in thick film resistors was investigated with regard to the gauge factor enhancement.

Buried resistors in low-temperature co-fired ceramics were studied to determine processing, microstructure, and electric properties.

(Bi,Pb) 2223 multifilamentary tapes with resistive barriers were fabricated, and transport AC losses were studied.

Research is presented concerning the use of SPICE simulations for device performance predictions. Mask tolerances, fabrication thickness tolerances and mask bias offsets are considered. The Monte Carlo analyses is discussed.

Noise properties linked to interconnect resistors of an interdigitated structured are examined.

Theoretical problems involving equivalent resistances of large or infinite networks of resistors have received substantial attention. We consider two actual networks. In the first, the resistance is measured across one end of a ladder whose number of loops is incremented until the precision of the multimeter is exceeded. In the second, resistances are measured across nodes near the center of a 12 by 12 square grid of resistors. These experiments are useful in the introductory physics laboratory as interesting examples of equivalent resistance, and can be added to a standard Ohm's law experiment. The square grid apparatus also can be employed for lecture demonstrations. In addition, this apparatus offers approximate experimental confirmation of complicated theoretical calculations for the equivalent resistance between two nonadjacent nodes of an infinite square grid. These experimental results are verified numerically.

This paper deals with an active gate drive (AGD) technology for high-power insulated gate bipolar transistors (IGBT's). It is based on an optimal combination of several requirements necessary for good switching performance under hard-switching conditions. The scheme specifically combines together the slow drive requirements for low noise and switching stress and the fast drive requirement for high-speed switching and low switching energy loss. The gate drive can also effectively dampen oscillations during low-current turn-on transient in the IGBT. This paper looks at the conflicting requirements of the conventional gate drive circuit design and demonstrates using experimental results that the proposed three-stage AGD technique can be an effective solution. Index Terms: Active gate drive, gate drive circuit, gate resistor, insulated gate bipolar transistor switching transient

An investigation was done on the effects of zero order harmonics produced in a 7.5 kva single phase transformer using dc produced by injection on the primary from an external source and also by half wave rectification on the secondary with a resistive load. The accuracy of the discrete fourier transform (dft) [1] for determining the dc component was also looked at, along with the ability of current transformers to detect a low frequency, or quasi-dc, component superimposed on an ac signal. Polynomial functions were developed to predict harmonic production, line current amplitude, input power, power factor, core losses, etc. as functions of the dc current value for both cases. Results show a strong similarity in produced current harmonics for both cases. The dft is an accurate tool for determining the value of a dc component. Passive current transformers are not able to accurately detect a dc, or slowly varying ac, component.

The present work alms at determining the dependence of the dc insulation resistivity on temperature and electric field for a super-clean low density polyethylene (LDPE) used in manufacturing modern high voltage ac cables. Resistivity measurements were made using relatively thick ([approximately]2 mm) samples at different temperatures and dc electric fields. based on the present experimental data, a mathematical model for the relationship between the insulation resistivity of the polymer, temperature and electric field was determined using: i) computer curve fitting techniques, il) Artificial Neural Networks (ANN) method. Comparison between the present results and previous measurements, using less clean grades of LDPE, indicates that the inherent dependence of the dc insulation resistivity of LDPE on temperature and electric field has not been appreciably improved by using an ultraclean polymer. It is concluded that the successful utilization of LDPE for HVDC cables will require the modification of such dependence. Keywords: Polyethylene, DC Cables, High Voltage, Polymer, Resistivity, Electric Field, Temperature, Matlab, Artificial Neural Networks.

The resistance between two arbitrary nodes in an infinite square lattice of identical resistors is calculated. The method is generalized to infinite triangular and hexagonal lattices in two dimensions, and also to infinite cubic and hypercubic lattices in three and more dimensions.

A study was conducted to examine the electrical characteristics of junctions and resistors grown using an all-NbN superconductor integrated circuit (IC) foundry process. Experimental results show that the fabricated junctions and resistors show repeatable trilayer characteristics and have reduced run-to-run variations in MgO film thickness. It was also noted that the IC foundry process produced larger wafer resistor spreads than what is desired.

Research was conducted to examine the performance of high-critical temperature superconducting quantum interference devices (SQUIDs) with resistively shunted inductances. It was found that the voltage modulation depth Delta-V of shunted 83 pH SQUIDs was substantially larger than that of unshunted SQUIDs with similar parameters and increases with the parameter gamma = R(sub n)/R(sub s) as expected from theory. Results indicate that significant improvements in high temperature superconducting SQUID magnetometer performance can be achieved by resistively shunting the SQUID inductance.

Research was conducted to examine experimental results and mathematical models for the resistiity of a noble metal film which connects two strips of superconducting yttrium barrium copper oxide (YBCO). The objectives were to determine the lowest achievable contact resistivity and to illustrate a very small variation with current of the contact resistance. Results indicate that there is a lower limit to the width of the finger geometry, beyond which the current flow along the YBCO fingers is reduced.

Research was conducted to examine Rapid Single Flux Quantum (RSFQ) T-flip flops operating up to 770 GHz and demonstrated at 4.2 K. The fabrication of the devices, which consist of either a resistively shunted or unshunted Josephson junctions, was done using a planarized Nb/AlO(sub x)/Nb trilayer process. T-flip flops with a reduced cell area, using self-shunted junctions with a minimum area of 0.06 micron2 operating to 770 GHz have also been demonstrated.

An efficient method for modeling the transient characteristics of distributed resistor-capacitor of ultra-large scale integration multilevel interconnections on complex topography was described. The method aimed to avoid the redundant works on both volume mesh and transient analysis associated with the finite-difference method. The method enabled the easy calculation of the transient characteristics of both parallel conductors and complicated configurations such as crossing lines, corners, contacts, multilayers and their combinations.

Poly SiGe bolometers were studied and characterized. The impact of resistivity, bias voltage, thermal conductance, thickness and dimensions of the active element on the device performance had been investigated. Findings demonstrated that the limiting factor for the performances of the device is the 1/f noise. By using the appropriate absorber and by optimizing device parameters, the bolometers were found to be suitable for realizing high-performance focal plane arrays.

A study was conducted to examine resistance changes resulting from piezoelectric charge densities in n-gallium arsenide mesa resistors against surface stress. Results confirmed the existence of the effects of piezoelectric charges in mesa resistors. Findings also suggested that the resistance changes from low-doped resistors supported an opposite sign for the resistors oriented in two directions. In addition, the surface stresses induced by the deformation of cantilever beams generated nonuniform stress distributions within the resistors.

Research was conducted to examine the uniaxial stress effects of AlGaAs/GaAs modulation doped heterojunction resistors. The transmission line method was utilized to separate components of the resistor stress coefficients based on sheet resistivity and contact resistance. A value for the piezoelectric constant e14 for Al0.4Ga0.6As of 0.26 Cm2. Aside from the sheet resistivity, it was found that the metal to semiconductor contact resistance also shifts with applied uniaxial stress.

Noise due to resistors and op amps in active RC and MOSFET-C filters is considered. Bounds for the signal-to-resistive noise ratio and signal-to-op amp noise ratio in state-space filters are given.

Bubble nucleation mechanism and heat transfer processes produced by micro-polysilicon line resistors having a typical size of 50x2x0.53 mum(super3), are addressed. A variety of unprecedented bubble formation phenomena were observed, such as stable and controllable bubble sizes during formation and bubble nucleation hysteresis. A one-dimensional electrothermal model, based on the conservation of energy to analyze the heat transfer process is established.

Distributed circuits composed of linear multiconductor transmission lines and terminated with nonlinear weakly active multiport resistors are considered. The line is represented as a linear dynamic multiport through recursive convolution relations and special considerations are given to some general properties of the line impulse responses. The convolution technique allows the mathematical description of these distributed circuits by means of a set of nonlinear algebraic-integral equations of Volterra type for the terminal voltages and currents. The conditions under which these governing equations can be reformulated as a set of Volterra integral equations of second kind in normal form are given with the explicit means for doing so. These conditions also assure the existence and the uniqueness of the solution. In particular if the terminal multiport resistors are strictly locally passive, then the normal form exists and the solution is unique. Transmission lines with terminal multiport resistors that are locally active may not admit a normal form for the governing equations, and hence, several solutions that have the same initial conditions are possible. In these cases a simple method is presented for revising the original network model so that the normal form exists, and hence, the uniqueness of solution is assured, under mild restrictions. Index Terms - Distributed circuits, existence and uniqueness of solutions, multiconductor transmission lines, normal forms.

In this paper, we discuss the stability of the characteristic curves for nonlinear resistive circuits including parasitic elements. Although the dc solution is determined by analyzing the nonlinear resistive circuit, its equilibrium point will be stable or unstable because every resistive element has a small parasitic component in practice. We consider here two parasitic elements: a capacitor between every resistor node and ground and an inductor in series with each resistor. Of course, the stability can be decided by solving the variational equation at each equilibrium point obtained by the dc analysis; however, this is very time consuming. We show here that the stability is mainly changed at the boundary of the presence of negative differential resistance (NDR) and the bifurcation points, such as turning and pitchfork points on the dc characteristic curves. The instability regions of the solution curve are easily found by both the locations of bifurcation points and NDR regions of the nonlinear resistors. Index Terms - Bifurcation points, curve tracing method, instability regions, parasitic elements, stability of characteristic curves.

Carbon black-chiral polymer composites were used to provide diagnostic differential resistance responses in the presence of enantiomers of chiral gaseous analytes. Vapors of (+)-2-butanol and (-)-2-butanol, (+)-[Alpha]-pinene and (-)-[Alpha]-pinene, (+)-epichlorohydrin and (-)-epichlorohydrin, and methyl (+)-2-chloropropionate and methyl (-)-2-chloropropionate were generated and passed over a chemically sensitive carbon black-poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate) (77% butyrate) composite resistor. Each enantiomer of a pair produced a distinct relative differential resistance change on the chiral detector, whereas both enantiomers of a set produced identical signals on achiral carbon black-poly(ethylene-co-vinyl acetate) (82% ethylene) detectors.

A study was conducted on the measurements of 1/f noise in bismuth ruthenate thick-film resistors in the frequency range of 1 Hz to 40 kHz. The dependence of the noise on the bias current, resistance in the range 1 kOmega to 400 kOmega and laser trimming effects were also considered. The technological importance of the findings is seen in the prediction of the approximate level of noise for any resistor made from the BIROX series compounds from the ink resistivity and the dimensions of the resistor.

Linear transmission lines with nonlinear terminal resistors are considered. Each resistor is assumed to be voltage controlled or current controlled and weakly active. These distributed circuits are shown to have a unique solution, which passes at a given instant through a given value, if the characteristics of the terminal resistors satisfy certain inequalities. In particular, if the resistors are locally passive, then the solution is unique. Transmission lines with terminal resistors that are locally active may admit several solutions that have the same initial value. In these cases, the uniqueness of solution is obtained adding 'small' capacitances in parallel to the voltage controlled resistors and 'small' inductances in series to the current controlled resistors. Index Terms - Normal forms, transmission lines, uniqueness.

A distributed circuit model was used to reduce the influence of resonances on washer style direct current superconductive quantum interference devices (SQUIDs) coupled to input flux transformers. The range of current biases was extended by placing a resistance of 1 ohm across each turn of a 137-turn coil coupled to a SQUID which reduced the structure in the voltage-flux curve. Intracoil resistors are not expected to affect the energy sensitivity of the SQUID.

A truncated cone, made of material of uniform resistivity, is given in many introductory physics texts as a nontrivial problem in the computation of resistance. The intended method and answer are incorrect and the problem cannot be solved by elementary means. In this paper, we (i) discuss the physics of current flow in a nonconstant cross-section conductor, (ii) examine the flaws in the 'standard' solution for the truncated cone, (iii) present a computed resistance found from a numerically generated solution for the electrical potential in the truncated cone, and (iv) consider whether any problem exists to which the standard solution applies.