Showing papers on "Equivalent circuit published in 1971"

Engineering Circuit Analysis

Abstract: The hallmark feature of this classic text is its focus on the student – it is written so that students may teach the science of circuit analysis to themselves. Terms are clearly defined when they are introduced, basic material appears toward the beginning of each chapter and is explained carefully and in detail, and numerical examples are used to introduce and suggest general results. Simple practice problems appear throughout each chapter, while more difficult problems appear at the ends of chapters, following the order of presentation of text material. This introduction and resulting repetition provide an important boost to the learning process. Hayt's rich pedagogy supports and encourages the student throughout by offering tips and warnings, using design to highlight key material, and providing lots of opportunities for hands-on learning. The thorough exposition of topics is delivered in an informal way that underscores the authors’ conviction that circuit analysis can and should be fun. Table of contents 1 Circuit Analysis and Electrical Engineering 2 Basic Components and Electric Circuits 3 Voltage and Current Laws 4 Basic Nodal and Mesh Analysis 5 Useful Circuit Analysis Techniques 6 The Operational Amplifier 7 Capacitors and Inductors 8 Basic RL and RC Circuits 9 The RLC Circuit 10 Sinusoidal Steady State Analysis 11 AC Power Circuit Analysis 12 Polyphase Circuits 13 Magnetically Coupled Circuits 14 Complex Frequency and The Laplace Transform 15 Circuit Analysis in the s-Domain 16 Frequency Response 17 Two-Port Networks 18 Fourier Circuit Analysis 19 State-Variable Analysis - *on Web Site Only Appendixes Appendix 1 An Introduction to Network Topology Appendix 2 Solution of Simultaneous Equations Appendix 3 A Proof of Thevenin's Theorem Appendix 4 A PSpice Tutorial Appendix 5 Complex Numbers Appendix 6 A Brief MATLAB tutorial Appendix 7 Additional Laplace Transform Theorems

Theoretical and Experimental Analysis of a Waveguide Mounting Structure

Abstract: The induced EMF method has been extended and applied to derive the driving-point impedance of a common waveguide structure used for mounting small microwave devices. An equivalent circuit is developed and discussed in detail. Theoretical impedance curves are presented demonstrating the circuit characteristics for various configurations of the mount. The driving-point impedance of this mount has also been considered experimentally. A novel measurement technique is used based upon the use of subminiature coaxial line to gain electrical access to the terminal pair located inside the waveguide. A model of the measurement circuit, which enhances the accuracy of the results, providing excellent agreement between the theoretical and measured values, is developed. The multilateral nature of the circuit allows consideration of the mount in the waveguide as an obstacle to any incident propagating mode. Some related measurements have been made using standard techniques for the H/sub 10/ mode. It is anticipated that this formulation will permit accurate design of many components which previously required empirical methods based on limited experimental data.

Theoretical performance of voltage multiplier circuits

Abstract: An expression for the equivalent source resistance of the capacitor diode voltage multiplier circuit is derived. The source resistance is found to increase as the cube of the multiplication factor, explaining the poor regulation observed with large multiplication. The distribution of capacitors that minimizes source resistance is presented. Good regulation is shown to be necessary for high efficiency, and to require relatively larger capacitors than needed for ripple filtering.

The Single-Cavity Multiple-Device Oscillator

Abstract: The output power from 12 IMPATT diodes has been combined in a single-cavity multiple-device oscillator. The oscillator is free from the well-known moding problem of multiple-device oscillators. The objective of this paper is to present the oscillator-circuit theory, which clearly indicates why this particular circuit configuration can give a stable operation free from moding problems. To handle the formidable equations necessary for the analysis, the eigenfunction approach is extensively used. The condition for stable operation, the noise performance, and the locking behavior of the oscillator are all discussed. The noise performance is similar and the locking behavior identical to those of single-device oscillators.

Computer analysis of nonlinear circuits, excluding radiation (CANCER)

Abstract: CANCER is a reasonably general circuit analysis program especially suited to integrated-circuit simulation. The program provides for the analysis of large circuits in the following four modes of operation: nonlinear d.c., large-signal transient, small-signal a.c., and thermal and shot noise. These subanalysis capabilities are intercoupled appropriately for convenience and efficiency. Internally, CANCER is a very general nodal analysis program that derives its efficiency from the exploitation of sparse matrix, adjoint, and implicit integration techniques.

Resonant response of harbours: an equivalent-circuit analysis

Abstract: The surface-wave response of a harbour to a prescribed, incident wave is calculated on the hypotheses of shallow-water theory, an ideal fluid, and a narrow mouth, M. An equivalent electrical circuit is constructed, in which the incidentwave displacement in M appears as the input voltage and the flow through M appears as the input current. This circuit contains a radiation impedance, ZM, which comprises resistive and inductive terms, and a harbour impedance, ZH, which comprises an infinite sequence of parallel combinations of inductance and capacitance that bear a one-to-one correspondence with the natural modes of the closed harbour, together with a single capacitor, which corresponds to the degenerate mode of uniform displacement and dominates the response of the harbour as a Helmholtz resonator. Variational approximations to ZH and ZM are developed. The equivalent circuit exhibits parallel resonance at the resonant frequencies of the closed harbour, ωn, and series resonance at a second set of frequencies, corresponds to the Helmholtz mode. A narrow canal between the coastline and the harbour is represented by a four-terminal network between ZM and ZH. It is shown that narrowing the harbour mouth and/or increasing the length of the canal does not affect the mean response of the harbour to a broad-band, random input except in the Helmholtz mode, but that it does increase significantly the response in that mode, which may dominate tsunami response. The general results are applied to circular and rectangular harbours. The numerical calculation of ZH for an arbitrarily shaped harbour is discussed.

Lateral photodetector operating in the fully reverse-biased mode

Abstract: A one-dimensional model of a reverse-biased lateral photodetector is analyzed. The effect of background illumination is considered. An ac equivalent circuit for the device is derived. From this equivalent circuit the transient response is calculated and device parameters that determine its characteristics are presented.

Complex plane analysis of heat capacity of polymers in the glass transition region

Abstract: A method is described which enables the direct measurement of relaxation times and relaxed and nonrelaxed heat capacities as a function of temperature. The apparatus designed is to be used as additional equipment to the Perkin-Elmer differential scanning calorimeter DSC-1B. The specimen is heated periodically with time instead of proportionally. The amount and phase of differential heat flow are measured. The parameters of an 'equivalent circuit' of a heat capacity model are fitted to the measured complex Cp values obtained at various frequencies and appropriate amplitudes of temperature. Further applications of the 'oscillating thermal analysis' are proposed.

Noise behavior of Schottky barrier gate field-effect transistors at microwave frequencies

Abstract: The noise behavior of a Schottky barrier gate field-effect transistor is investigated by the use of the noise equivalent circuit. The influence of the carrier velocity saturation is estimated. The noise parameters are calculated by taking into account the influence of parasitic resistances. Measured and calculated noise parameters show good agreement in the frequency range 2-8 GHz.

Gyrator implementation with integrable current conveyors

Abstract: An easily integrable circuit implementation of a current conveyor is presented. A low frequency high-Q gyrator realization employing current conveyor building blocks is discussed. Circuit design techniques to alleviate semiconductor device limitations are considered.

Broad‐Band Transducers: Radiation Field and Selected Applications

Abstract: In many applications, broad‐band ultrasonic transducers capable of producing short video pulses are required. Previously, plane‐wave analysis with equivalent circuits has proven successful in predicting pulse shape in the time and frequency domains. The present approach is to recognize that piston sources radiate nonplanar waves, and that the frequency spectrum of a broad‐band piston source can be measured experimentally. With the spectrum as a weighing function for the field profiles of a monofrequency piston source, a superposition is performed to find the pressure and phase profiles in the radiation field of a broad‐band transducer. Experimental measurements are presented that take advantage of the broad‐band pulse technique combined with spectrum analysis. These include thickness gauging of thin materials and interface layers, and relative viscosity measurements.

Power Transformer Core Behavior Under Transient Conditions

Abstract: The solution of an electric circuit problem is only valid if the circuit elements have been validly modelled. The iron-cored coil is a common nonlinear circuit element, especially in power system circuits, where the iron core is laminated grain-oriented silicon-iron sheet. This paper attempts to show that eddy-current loss modelling in such a core is at least as important as hysteresis loss modelling, and demonstrates the accuracy of linear modelling of the eddy-current effect. If the circuit analyst has confidence in this complete model he can then decide which aspects of the model can be ignored with impunity when studying such circuit phenomena as ferroresonance, subharmonics and inrush current.

ECAP II-a new electronic circuit analysis program

Abstract: ECAP II is a nonlinear d.c. and transient circuit analysis program capable of handling circuits larger than 1000 branches. It uses a free-format problem-oriented input language for describing the circuit parameters and topology. The program includes a nested model feature that permits the user to store in a model library circuit descriptions of devices, subcircuits, etc., for subsequent recall and insertion into larger circuits. Nonlinearities can be specified by means of tables, certain built-in functions such as the diode equation, and Fortran subroutines. All circuit elements can be made to depend on any current or voltage, on other circuit parameters, or on time itself. The user may specify which variables are to be printed out or plotted and what type of analysis is to be carried out. Diagnostics are provided to pinpoint errors in the input format and/or inconsistencies in the circuit description. A number of new mathematical and programming techniques are incorporated in the program, including sparse matrix storage and computation, dynamic storage allocation, and variable order implicit integration.

Analog performance limitations of charge-transfer dynamic shift registers

Abstract: Charge transfer dynamic shift register operation is described and a linearized analysis presented to relate the charge transfer properties to the performance of an n-stage register. An approximate small signal equivalent circuit is also derived to illustrate the similarities to a matched transmission line and the reactive and resistive elements of the line are related to charge transfer and loss characteristics of each stage of the register. The results are expected to be applicable to charge coupled devices and shift registers based on bucket brigade electronics.

Analytical Models for Saturated Synchronous Machines

Abstract: Most equivalent circuit models for synchronous machines have either neglected saturation or used only one saturable reactance which was made a function of one or more machine variables. The approach of this paper is, first, to determine the regions of magnetic saturation and to identify the magnetic flux variable on which each depends. Analytical models are then developed in which each saturable region of the machine is represented by a nonlinear parameter, the value of which is dependent on only one node voltage.

A Design Method for Meander-Line Networks Using Equivalent Circuit Transformations

Abstract: Many types of coupled structures are used to design microwave filters and equalizers. One such structure is the array of coupled parallel commensurate conductors called a meander line. There are several analysis techniques that may be used to find the equivalent circuit of a meander line. However, these do not provide exact design equations. In this paper, meander-line networks are analyzed and synthesized using the graph-transformation technique. The equivalent circuits of one- and two-port meander-line networks will be developed by using the transformation method, and it will be shown that meander-line networks can be easily designed by using the electronic computer.

Equivalent Circuit of Frog Atrial Tissue as Determined by Voltage Clamp-Unclamp Experiments

Abstract: The equivalent circuit that has been used in the analysis of nerve voltage-clamp data is that of the membrane capacity in parallel with the membrane resistance. Voltage-clamp experiments on frog atrial tissue indicate that this circuit will not suffice for this cardiac tissue. The change in membrane current associated with a step change in membrane potential does not show a rapid spike of capacitive current as would be expected for the simple parallel resistance-capacitance network. Rather, there is a step change in current followed by an exponential decay in current with a time constant of about 1 msec. This relatively slow capacitive charging current suggests that there is a resistance in series with the membrane capacity. A possible equivalent circuit is that of a series resistance external to the parallel resistance-capacitance network of the cell membranes. Another possible circuit assumes that the series resistance is an integral part of the cell membrane. The data presented in this paper demonstrate that the equivalent circuit of a bundle of frog atrial muscle is that of an external resistance in series with the cell membranes.

Design of Hairpin-Line and Hybrid Hairpin-Parallel-Coupled-Line Filters

Abstract: Hairpin-line filters are compact structures particularly suited for microstrip and TEM printed circuit realizations. Two types of hairpin-line filters are described in this paper. They are shown in Figs. 1(a) and (b). The image impedance and propagation constant for the infinite periodic hairpin-line has been given previously. Equivalent circuits for several periodically-terminated lines, including the hairpin line were discussed by one of the authors at the recently-concluded IEEE sixth region conference. However, for finite length hairpin-line filters, neither exact or approximate design equations, nor equivalent circuits have been reported. The exact equivalent circuits for the filters of Figs. 1(a) and (b) have been rigorously derived and are presented in Figs. 2(a) and (b), respectively, for the most important case in which coupling beyond nearest neighbors is negligible. These circuits are topological, but not exact, duals of the well-known interdigital and half-wave parallel-coupled-line filters. Consequently, the exact design tables and approximate design equations may be used in designing hairpin-line filters.

Experimental Determination of Exact Equivalent Circuit Parameters of Synchronous Machines

Abstract: For stability studies of large power systems, accurate representation of the synchronous machine is required. As pointed out by Canayl, the conventional equivalent circuits for synchronous machines do not give accurate computed field voltage and current values. He suggested several circuits and showed good agreement between his test and calculated results. His circuit parameters were calculated from design.

Very high impedance input circuit

Abstract: Disclosed circuit includes two series-connected operational amplifiers A1 and A2 inverter connected with resistive negative feedback so that their inputs are substantially and at least virtually grounded; a feedback loop including a resistor coupled between the output and input terminals of the series of operational amplifiers for increasing the input impedance of the circuit; and means of controlling stability and of correction comprising, a capacitor C in the feedback loop circuit, and at least one intermittently-operating DC error signal correction circuit.

Orthogonal transformation circuit using hadamard matrices

Abstract: An orthogonal transformation circuit in which unit transformation circuits are connected in cascade in accordance with a desired order of transformation. Each unit transformation circuit comprises a first delay circuit which delays discrete signals by a fixed time, an arithmetic circuit which provides the sum and difference between input and output signals of the delay circuit, a second delay circuit which delays the difference signal of the arithmetic circuit by the same delay time as that of said first delay circuit, and a gate circuit which provides output signals such that the sum signal from the arithmetic circuit and the difference signal from the second delay circuit are alternated at a fixed time interval.

Resonant techniques for establishing the equivalent circuits of small discontinuities in microstrip

Abstract: The accurate measurement of small discontinuities in microstrip by conventional means is limited by the imperfections of the microstrip to coaxial transition. By using a resonant technique where such imperfections cause only 2nd-order errors, the equivalent circuit of microstrip discontinuities can be measured. To demonstrate the method, a 90° corner, with and without a chamfer, has been measured.

Connection Routing Algorithm for Printed Circuit Boards

Abstract: A generalized algorithm for forming interconnections between points on a multilayer circuit board is described and evaluated. The algorithm treats interconnections on individual layers and connections between layers by means of plated holes. Generalizing the well-known Lee algorithm and using its terminology, this algorithm makes use of a coded C array that is stored in memory and records the state of the multilayer circuit board. Completed paths, possible remaining paths between points to be connected, and circuitboard interconnection restrictions are recorded in the coded C array. The algorithm consists of five iterative steps that involve decisions on the basis of the state of the circuit board as stored in the C array. All possible routes are attempted, and the routing sequence is stopped when the path is completed or all attempted path routes are exhausted. A number of modifications to the algorithm permitting various circuit connection constraints to be satisfied are also presented. The algorithm has been programmed for a GE-635 computer. Typical results for some of the printed circuit boards that were used to evaluate the algorithm are included.

Digitally controllable variable active rc filter

Abstract: The several transmission characteristics of an active RC filter are adjusted by digital control of passive networks included at particular points in the filter circuit. Each network includes a plurlaity of passive circuit elements connected either in series or in parallel, each circuit element having a switching element in circuit relation thereto for selectively preventing current from flowing in the associated circuit element. Each switching element is uniquely controlled by the logical condition of a predetermined place of a binary control quantity. The values of the elements in a given network are related by a geometric progression such that the filter characteristic controlled by that network varies linearly with the associated binary control quantity.

Assessing model adequacy and selecting model complexity in integrated-circuit simulation

Abstract: A method is described that selects, for each transistor in a circuit, the model of least complexity that will give acceptable accuracy. The capability to assess model adequacy derives from a self-consistency test in which the values of currents and voltages computed in a simulation of the circuit behavior are compared with onset parameters, to determine whether these computed values are consistent with the approximations underlying the device models used in the simulation. The onset parameters for a model are the terminal currents and voltages above or below which the model fails to give a satisfactory representation of device behavior. The authors set forth the onset parameters for the Ebers-Moll model and discuss their determination by terminal measurement and by calculation based on the transistor makeup. The paper limits consideration to the static behavior of transistors operating in the forward-active mode.

Interdigital piezoelectric Rayleighwave transducer: an improved equivalent circuit

Abstract: A more accurate representation of an interdigital array is obtained by using an equivalent circuit intermediate between the crossed-field and in-line-field models, with negative capacitance, velocity, length and coupling dependent on the electrode-width/gap-between-electrodes ratio

Mount-independent equivalent circuit of the S4 diode package

Abstract: Broadband-admittance measurements have been made on dummy S4 diode packages mounted in a coaxial line. By comparing these with the theoretical admittance of a lumped-component equivalent circuit for the package and its mount similar to that of Getsinger, a consistent set of mount-independent equivalent-circuit parameters for the package has been derived.

Low Impedance Supply for Tunnel Junctions

Abstract: A circuit is described which employs an operational amplifier arranged as a voltage follower to obtain output impedances as low as 0.001 Ω. Direct drift and noise levels are such that the circuit can be used as both a dc and ac voltage source for tunnel junction measurements. A comparison is made with a similar ac conductance bridge recently reported in the literature and a simple modification of the latter circuit is suggested.