The purpose of this review paper is to show that the concept of modes does apply to any linear time invariant circuit. This is accomplished by reducing the network equations to the standard vector form \dot{y} = Ay + f . In particular, it is shown that 1) any free oscillation of a linear circuit can be thought of as a superposition of non-interacting modes, 2) in the case of free oscillations, the amount of excitation of each mode can easily be expressed in terms of the initial conditions, 3) any forcing function excites each mode independently, and finally, 4) the resonance phenomenon is easily interpreted and the importance of the proper type of excitation is made obvious. Vector notation is used throughout. Examples of RC, RLC and active circuits are included.

Modes in Linear Circuits

When a number of negative resistance elements are interconnected, a multistable voltage-current characteristic will be generated. The form of this composite characteristic will depend on the mode of interconnection and on the characteristics of the individual elements. 2n stable states can be generated using n negative resistance elements when the individual characteristics of the elements obey certain rules derived herein. A modified flip-flop circuit has been developed whose characteristic can be precisely tailored to fulfill the requirements. Several applications to logical functions are discussed. Potential advantages of this method lie in the circuit simplicity resulting from an intrinsic feedback operation which replaces separate logical functions.

Composite Characteristics of Negative Resistance Devices and Their Application in Digital Circults

This work is intended to historically commemorate the one hundredth anniversary of the invention of a new type of electronic circuit, referred to in 1919 by Abraham and Bloch as a multivibrator and by Eccles and Jordan as a trigger relay (later known as a flip-flop).,The author also considers the circuit-technical side of this new type of circuit, considering the technological change as well as the mathematical concepts developed in the context of the analysis of the circuit.,The multivibrator resulted in a “circuit shape” which became one of the most applied nonlinear circuits in electronics. It is shown that at the beginning the multivibrator as well as the flip-flop circuits were used because their interesting properties in the frequency domain.,Therefore, it is a very interesting subject to consider the history of the multivibrator as electronic circuits in different technologies including tube, transistors and integrated circuits as well as the mathematical theory based on the concept from electrical circuit theory.

100 years multivibrator-history, circuits and mathematical analysis

A Transistor Flip-Flop Full Binary Adder

Tests are described which have been carried out to investigate the self-starting performance of the simple saturating transistor-astable-multivibrator circuit under different conditions, on connection of the d.c. supply to the circuit. These tests reveal that failure to start is controlled by several complex interacting factors. In general, high-gain transistors are more prone to failure to start than low-gain transistors in any given circuit. A theoretical discussion of the results obtained is included.

Self-starting performance of astable-transistor-multivibrator circuits

The basic junction-transistor multivibrator circuit is analyzed from the point of view of a circuit designer who Wishes to know: (a) how to predict the performance of a particular configuration, and (b) how to synthesize a multivibrator circuit, which may be either astable, bistable, or monostable, from a given set of specifications. The analytical method consists of breaking the multivibrator circuit (two basic, well-known configurations are treated) at a suitable point and using, the two terminals thus obtained as a driving-point pair to derive a useful V-I characteristic. In part I of the paper, the static driving-point resistance characteristics arc derived theoretically and compared to experimental measurements. In part II, transient and high-frequency effects are considered and the two-terminal analysis is extended to derive a prediction of the maximum frequency, or pulse repetition rate, at which the regenerative mode of operation can take place. Part III of the paper treats the problem of circuit synthesis. Using the results of parts I and II, straightforward methods are developed which permit the circuit designer to uniquely determine the seven circuit parameters which must be specified in the design of symmetrical multivibrators. Several design examples of astable, monostable, and bistable configurations are given.

J. Suran

Papers

Two-Terminal Analysis and Synthesis of Junction Transistor Multivibrators