Showing papers on "Equivalent series resistance published in 1970"

Self-Excited Oscillations in a Transmission System Using Series Capacitors

Abstract: Self-excitation can result from using series capacitors in EHV transmission circuits if the series compensation is large and the circuit resistance small. Such a condition can be realized in a highly compensated transmission line using bundle conductors. An analytical approach to solve for the borderline conditions between stability and instability is presented. The analysis presented is suitable for the simultaneous consideration of both electromechanical (hunting) and primarily electrical (self-excitation) oscillations using lumped circuit constants, or for cases of distributed circuit parameters (long lines and/or solid-rotor generators). Numerical examples are included.

Integrated circuit process utilizing orientation dependent silicon etch

Abstract: Orientation-dependent etching is employed in the fabrication of a monolithic semiconductor circuit network to provide electrical isolation and increased packing density, while minimizing collector series resistance and output capacitance. Collector contact to a transistor component is made by the direct metallization of a buried low-resistivity substrate region exposed by the preferential etching operation.

Effectiveness of Series Capacitors in Long Distance Transmission Lines

Abstract: The effectiveness of series capacitors used with long distance transmission lines in improving system stability is analyzed. Compensation efficiency is defined as the effectiveness of series capacitors. The influence of various factors on compensation efficiency such as capacitor location, line length, and degree of series compensation is investigated. Proper use of shunt reactors with series capacitors, in addition to limiting power frequency over- voltages, increases the maximum power transfer. Analytical expressions are included to aid in the calculation of compensation efficiency for a few typical cases. Curves are also presented indicating the critical value of shunt Mvar required for various degrees of series compensation and line lengths.

An evaluation of the methods of determining solar cell series resistance

Abstract: Solar cells lumped series resistance determination, comparing dark forward characteristics method and two light level approach

Schottky barrier diode

Abstract: Anisotropic etching is employed in the fabrication of a Schottky barrier diode to provide a recessed geometry having a guard ring of reduced area, thereby avoiding the objectionable degree of parasitic capacitance found in related planar devices. A low series resistance is also provided since the anisotropic etching step inherently permits a precise control of the distance between the surface barrier and a buried substrate layer of low resistivity.

Lumped-Elements in Microwave Integrated Circuits in the 1-12 GHZ Range

Abstract: Lumped elements have found increasing use in microwave integrated circuits at low UHF and S-band frequencies. At this laboratory they have been used in various circuits such as filters, quadrature hybrids, and impedance matching networks for high-power transistor amplifiers. Limiting the use of lumped elements has been: (1) the uncertainties of the reactance and Q's of the elements at frequencies above 2.5 GHz, and (2) the difficulty of fabricating the high-Q components necessary for large impedance transformations to low-impedance active devices. The past difficulty in measuring the reactance and Q values above S-band has been the unavailability of a measurement system at high frequencies that is compatible with the size of the element. However, suitable resonant techniques have now been developed for frequencies from 1 to 12 GHZ. Lumped inductors and capacitors fabricated at this Iaboratory have been measured by these new techniques. The results demonstrate that high-Q capacitors have been achieved by recent improvements in thin-film dielectric processing, and that capacitors and single-turn inductors are "truly lumped" through 10 GHz.

A New Method of Measuring Dielectric Property of Very-High-Loss Materials at High Frequencies

Abstract: This paper presents a circuit system functioning as a capacitance meter suitable for very-high-loss material with a wide range of application in various fields of scientific research and industrial operation. The minimum equivalent parallel resistance of the specimen to be measured reaches as low as 50 ohms and the measuring range of capacitance is from about 0.1 ~ 1000 pF at 2 MHz. Some experimental data are given for the appreciation of its characteristics.

Accurate Immittance Measurements at Frequencies up to 20 MHz

Abstract: Immittance-measuring facilities have been developed that yield high accuracy over a wide immittance range at frequencies up to 20 MHz. The achievement of accuracy at high frequencies required that the errors resulting from residual immittances be kept small, which in turn required development work in bridge design, calibration techniques, measurement methods, and the intercomparison of measurement results. These activities included the design and calibration of unity-ratio admittance bridges, the use of additional circuitry with these bridges to measure small impedances, and the modeling of the impedances of small-valued inductors. Examples of the resulting accuracies for the values assigned to high-Q inductors are at 1 MHz, approximately ± t(0.1 percent+0.5 nH) in inductance and ±(0.01 Q percent+0.3 mQ) in resistance for 50-nH to 100-?H inductors; and at 10 MHz, ±0.5 percent in inductance and ±0.5 Q percent in resistance for 0.5-?H to 3 IH inductors.

Degradation of the oscillator performance of read diodes due to space-charge and series resistances

Abstract: It is shown that the bias current density is a very important parameter in the operation of Read-diode oscillators. A degradation factor is derived for the d.c./r.f. conversion efficiency due to the space-charge resistance of the drift region and the series resistance. Optimisation of the generated r.f. power is discussed.

Hafnium dioxide capacitors for microwave integrated circuits

Abstract: Anodized, sputtered hafnium (hafnium dioxide) produces a high-dielectric-constant (∼40) capacitor that has low electric loss. Measurements to 10,5 GHz on capacitors in the range 6 to 96 pF show good performance as dc blocks and bypass capacitors in actual use. Series resistance at 3 GHz is below 0.3 Ω series inductance is of the order of 50 pHy. Temperature effects, processing techniques, and measurements are described. These capacitors are compatible with standard microwave-integrated-circuit processing techniques used to make both lumped and distributed circuits. The results described were obtained on chip versions of these capacitors.

Self-Isolated Transistor Structures of Bipolar Integrated Circuits

Abstract: Self-isolated transistor structures for bipolar integrated circuits are proposed. Some of the advantageous features of the proposed structures are; negligible minority carrier storage in collector region, low collector series resistance and large current handling capability, high packing density, and ease of processing. Cutoff frequency of about 600 MHz was observed for the graded base structure, and about 400 MHz for the uniform base structure. It is also shown that the current handling capability is improved. Epitaxial growth is one of the critical steps in producing self-isolated bipolar integrated circuits. A discussion is given for the specification of the epitaxial layer. In order to minimize the back diffusion from the buried layer to the base, a new possible way of processing is proposed which makes use of the simultaneous diffusion of Ga, As, and P.

Research and development of silicon solar cells for low solar intensity and low temperature applications

Abstract: Problems were identified, using N/P solar cells at low temperature and low intensity; these problems were solved and the solutions incorporated in a manufacturing procedure. Theoretical analysis of the effects of low temperature and low intensity on the various solar cell characteristics indicated that the following behavior might be expected: (1) lower short circuit current,(2) higher open circuit voltage,(3) series resistance becoming less significant, and (4) shunt resistance becoming more critical.

Effect of electrical discharge on silicon solar cell characteristics

Abstract: It is generally believed that there is no possibility of deterioration occurring in silicon solar cells on the surface of the earth. As one of the tests for their environmental capabilities, the effect of electrical discharge on series resistance, curve power factor, conversion efficiency and spectral response is investigated. The cells are found to exhibit unexpectedly large and permanent deterioration in their characteristics. Some of the phenomena which might be responsible for the observed degradation are pointed out and discussed.