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A new open circuit step cavity resonator for continuous and contactless monitoring of sheet moisture content is proposed. The return loss as well as the perturbation in the resonant frequency of the resonator due to variations in the moisture content of sample paper passing through the cavity are monitored in real time by terminal devices and interpreted to display the paper moisture content in digital or analog form. [ABSTRACT FROM AUTHOR]

The paper deals with parametric phenomena in a non-linear oscillating circuit with negative resistance. The differential equations of the parametric excited circuit, for the case where the self-oscillations' amplitude is smaller than the amplitude of the pumping signal, reduce to the equations of Hill and are solved by an original method (Samoylo and Spasov 1970). In an investigations of the transient and steady-state regimes the real non-linearity of the reactive element in the oscillating circuit is considered. The mode of forced oscillations and the resonance of the second and third subharmonics of the pumping signal are discussed. The experimental results agree well with theory.
The results given in the paper may be of interest in an investigation of oscillating circuits, utilizing semiconductor elements with negative resistance : tunnel diodes, Gunn diodes, avalanche transit-time diodes, etc. [ABSTRACT FROM AUTHOR]

The paper presents an active RC network which exhibits selective, all-pass and notch characteristics with simple adjustments of parameters. Two gain-parameters and passive-resistive elements are kept adjustable for this purpose, which also help to obtain variable selectivity and desired center frequency of the filter in the appropriate configurations. Discussions on the Q factor sensitivity of the filters have also been appended.
This paper describes an active RC second-order filter which can be adapted to operate in three different modes. As a band-pass filter it can be designed to have adjustable bandwidth and center frequency, which shows that the circuit may be used as a tuned selective filter. Secondly, depending on the choice of the system parameters, the circuit behaves as an all-pass network with adjustable delay. Finally, it is shown that the circuit operates as a very good rejection filter having continuously adjustable selectivity and notch frequency with no change in the shapes of its transmission characteristics. [ABSTRACT FROM AUTHOR]

The paper describes a circuit containing a junction transistor and a F.E.T. which behave as a one-port voltage controlled negative resistance of adjustable magnitude.
One-port negative resistance circuits, being very useful in synthesis of network functions, filter design and the design of regenerative circuits, have been developed by many authors (Waldmann and Beiri 1955, Indiresan 1959, Nagata 1965, Martinelli 1966). In this paper a new voltage controlled negative resistance circuit employing a transistor and a F.E.T. has been proposed which is different from the existing circuits regarding its network topology. The circuit requires no internal bias. As this circuit utilizes one transistor and a F.E.T., the circuit can be readily fabricated as an integrated module. [ABSTRACT FROM AUTHOR]

The expressions previously derived by the author for the resistance parameters of the composite transistors are used to investigate theoretically the open circuit characteristics of the compound configuration consisting of two-point contact type transistors. It is found that the system has, in general, a much smaller current gain, voltage gain, input resistance and higher output resistance. The characteristics are greatly modified when the second-point contact type transistor is replaced by a junction type.
Recently the author, in his paper (Singh 1969), has derived the general expressions for the resistance parameters of the composite transistors in terms of the open circuit parameters of the individual transistor. The characteristics of the compound systems in all the three configurations were, however, not theoretically investigated although these have already been discussed by Suen (1968) in terms of the hybrid parameters. Therefore in this paper the author presents the quantitative analysis of the characteristics of the Darlington configuration on the basis of its resistance parameters. [ABSTRACT FROM AUTHOR]

The design of a monolithic current-controlled current source (CCS) based on the intrinsic matching properties of similar adjacent transistors is described. Experimental and theoretical results are presented and compared. This CCS has been specially tailored for use in a four-quadrant multiplier circuit discussed in a earlier communication (Scholtzhauer and Viswanathan 1972).
This paper describes a current-controlled current source (CCS) designed as an input driving module for a four-quadrant analogue multiplier (Scholtzhauer and Viswanathan 1972). This application requires a broadband, stable and linear unity current-gain block with high output resistance, low input resistance and low input offset voltage, plus a special-purpose second output. This output should be formed as I = I/( + 1), where I is this auxiliary output, I is the main output and is the common-emitter gain of a single transistor matched with the devices in the multiplier circuit. [ABSTRACT FROM AUTHOR]

It is well known that there is a hysteresis effect in the Schmitt trigger circuit. In the present paper, the author proposes a negative hysteresis threshold circuit which consists of a cathode-coupled trigger circuit with a CR delayed feedback loop. This circuit can be set to remove any hysteresis by adjusting the delayed feedback loop gain.
A non-linear analysis is developed on the above circuit, using the phase-plane method together with the experimental results. [ABSTRACT FROM AUTHOR]

An active RC realization scheme of a bilinear RL impedance is presented. The active device incorporated is a current-controlled current source. Discussions pertaining to Q-factor maximization and sensitivity minimization are also appended. 1. Introduction
A number of different circuits have recently been reported for the active RC realization of inductors (Riordan 1967, Keen and Peters 1967, Patranabis 1970 a, b). The inductors obtained in these circuits may be ideal, real or bilinear RL type, depending on the circuit configurations. The realization of inductor has been pursued from the synthesis viewpoint as well. The synthesis schemes are, in general, very much constrained and are therefore not much of practical consequence (Sipress 1961). A generalized voltage-controlled voltage source (VCVS) scheme has been published recently (Rao and Venkateswara 1970). This method requires two active sources. The present paper is intended to describe a simple realization scheme of a bilinear RL impedance incorporating a single active device of the current-controlled current source type (CCCS). The inductor is frequency dependent, and at a particular frequency the Q-factor of the inductor becomes maximum. The value of this maximum Q can be adjusted to be quite large. The sensitivity of the Q-factor with respect to the various circuit parameters has been studied with reference to minimization possibilities. The circuit has been experimentally realized and the results are found to be in agreement with the theory. [ABSTRACT FROM AUTHOR]

The paper describes the design and construction of a new type of frequency meter. In the present instrument the important characteristic of a monostable circuit changing its state by an input impulse signal has been utilized for measuring the frequency of the input signal.
The instrument covers a frequency span from 10 HZ to 10 kHZ in three separate ranges, with a linear scale of indication. A permanent magnet moving coil type sensitive meter has been used as the indicating element. A consistency of better than 1% has been obtained between the calibrations of the three ranges using the same scale. The authors feel that they have been able to offer a novel frequency meter of good resolution, wide frequency coverage and rugged construction. The instrument requires no special maintenance skill. [ABSTRACT FROM AUTHOR]

A lumped model for the Read avalanche diode is combined with the equivalent circuit for the package of the diode to give a state equation describing the complete chip-package system.
A computer program calculates the component values for the total equivalent circuit by parameter variation, using results obtained from a microwave network analyser.
The results show that the reflection coefficient, as calculated from the equivalent circuit, agrees with measurements to within 5% in the frequency range of 7-11 GHz.
This paper presents a method of small-signal characterization of avalanche diodes, including the encapsulation of the active chip, from reflection coefficient measurements on a network analyser, and with the aid of a digital computer. The computer program uses a direct search method (Bandler 1969) of parameter variation to calculate the parameters of the model for the complete chip-package system. The model used for the chip is an extension of a lumped model developed by Corm et al. (1970) and that used for the package is discussed by Getsinger (1966). The technique of analysis results in equations that may be written in state-space form (Kuh and Rohrer 1965), allowing inclusion, if necessary, of equations describing the circuit external to the diode. [ABSTRACT FROM AUTHOR]

A negative feedback circuit using one operational amplifier has its Q factor enhanced through the introduction of an additional voltage amplifier with positive finite gain in the feedback loop. The new network has two useful outputs. If a twin-T is connected in cascade with the network input terminals the overall circuit is suitable for the realization of biquadratics or third-order low-pass elliptic functions. The network sensitivity is very low.
It is well known that the main problem with most active networks is their sensitivity to variations in their component values. Certain negative feedback active networks have low sensitivity but suffer from low selectivity for a practical range in the values of their components. This disadvantage prevents the use of these networks in the realization of high selectivity filters. It is possible to improve the selectivity of such circuits by introducing positive feedback (Geffe 1968), but this method also results in higher network sensitivities. In this paper the selectivity of a well-known second-order active section is increased without the use of positive feedback and without de-rating the network sensitivity. Although the resulting section is not completely new, it is thought that the method of deriving it is new and very useful, and that its features and use in the realization of third-order elliptic filters and biquadratic functions are worth mentioning. Experimental results are also included. [ABSTRACT FROM AUTHOR]

The paper describes a method for the numerical study of the growth of current in circuits which comprise a non-linear inductor. The non-linear magnetization curve is supposed to be composed of a number of linear chords and an analytical expression for current is developed for each chord. Computation of current over any chord at equally spaced points along the time axis is carried out until the difference of the magnitude of this current and that at the end of the chord is the minimum. The method of solution has been explained taking the numerical illustration of the field circuit of a generator where the impressed potential difference is constant, the solution being obtained with the help of a digital computer. The graph showing the nature of the build-up of current is in perfect agreement with experimental data. The method has also been extended to circuits where the impressed voltage is alternating as in the case of an iron core transformer. [ABSTRACT FROM AUTHOR]

Protective schemes require interconnection of basic functional units in varying degrees of complexity. Distance protection of the switched type is an example of the interconnection of many of the units. In this paper a new faulty phase selection scheme for switched distance relays, using programmed diode matrix, is developed. The scheme retains all the advantages of a static phase selector and in addition offers a considerable simplification of the circuitry.
Theoretically, any complete three-zone distance protection scheme would need eighteen ohmic measuring elements along with four fault detectors to cater for the ten varieties of phase to phase and phase to earth faults. The resulting extravagance of cost and of panel space has led to the use of a lesser number of ohmic units by employing a single unit for more than one purpose. [ABSTRACT FROM AUTHOR]

A transistorized point on a wave selector which gives a 200 volts positive pulse at any desired point on an input sine wave is explained. It can work either in single shot or in repetitive mode. The circuit is synchronized with the input sine wave shape on any point of which a pulse is needed, and the output voltage pulse is obtained only when the sinusoidal voltage is present. It also gives a positive trigger pulse which can trigger an oscilloscope sweep circuit. The trigger pulse leads the output pulse so that at least one cycle of the sine wave will be displayed on the oscilloscope screen before the output pulse.
In this paper we report on a newly developed transistorized point on a wave selector which gives a positive 200 volts pulse whose position with respect to the input sine wave can be adjusted from 0degrees to 360degrees. Another positive pulse 30 milliseconds before the output pulse is also generated which can be used to trigger the sweep of an oscilloscope. This is provided so that at least one full cycle of the power frequency voltage is seen before the high current to the lightning arrester is triggered, which is a requirement for the operation duty cycle tests on lightning arresters. This delay can be adjusted by suitably changing the value of R (fig. 2), so that the sweep of the oscillograph can be triggered at whatever time required earlier to the output pulse. [ABSTRACT FROM AUTHOR]

It is shown that a transfer function with a high-Q factor and zero sensitivity to temperature variations can be realized by an active RC circuit using a negative-emittance converter. It is assumed that all resistors have the same temperature coefficient, and similarly with the capacitors. Experimental results confirm the theory.
It will be shown in this paper that NIC circuits can have zero sensitivity when operational amplifiers are used. This result is based on the design approach whereby sensitivity contributions of some passive components are cancelled by contributions of other passive components. Here it is assumed that ail components of the same kind (resistors or capacitors)have the same temperature coefficient. This assumption is valid for integrated circuits, which are of primary interest here. [ABSTRACT FROM AUTHOR]

A neuristor of a constant K two-line active circuit proposed by the authors was realized and the dependence of neuristor characteristics on the circuit parameters was obtained. It is known that the neuristor proposed as a micro-logic device has many advantages. However, no functional device which works as the neuristor has been completed. The proposed neuristor models have not been satisfactorily developed as a micro-electronic device because they cannot be integrated due to their structural difficulties, or even if the integration is realized, the relation between the structure and the neuristor characteristics was often obscure.
From the above point of view, a two-line circuit is proposed in this paper which is easily integrated because of its simple structure and is easy to explain theoretically. The neuristor is realized by a lumped-constant K active circuit to obtain the dependence of the neuristor characteristics on the circuit parameters. As a circuit, a series and a parallel type neuristor are used into which an S-shaped and an N-shaped negative resistive element are inserted, respectively.
First, by transmitting pulses the circuit shows that the neuristor characteristics are realized by the constant K circuit. Next the dependence of the neuristor characteristics on the circuit parameters is obtained as a function of the impedance of the circuit element, and finally, to explain theoretically the measured results, the circuit is analyzed by Gauss--Seidel's method which improves the conventional phase plane analysis.
As a result, it is demonstrated experimentally that the neuristor can be realized using the constant K two-line circuit. The relation between the neuristor characteristics and the circuit parameters is also obtained. Almost all the experimental results are proved theoretically. The difference of the neuristor characteristics between the S-shaped and the N-shaped negative resistance element is demonstrated. Thus new knowledge... [ABSTRACT FROM AUTHOR]

In order to determine dynamic currents and voltages of a circuitry containing transistors, dynamic transistor characteristics must be known. This paper shows how to derive dynamic transistor characteristics for a charge-controlled transistor model by a synthesis of Ebers and Moll's static and Beaufoy and Sparkes' dynamic transistor relations. Dynamic transistor quantities may then be determined by two methods: one may solve the related system of dynamic circuit equations directly, and another may solve the system of corresponding ' adjoined static ' circuit equations leading to 'adjoined static' quantities from which dynamic quantities may then be computed. Adjoined static quantities are time-dependent quantities which would be observed if all base-charging currents were supplied from wells inside the transistor base, whereas in reality they are supplied by sources outside the base, leading to the observation of corresponding dynamic quantities. The possibility of deriving dynamic from adjoined static quantities follows from the basic assumptions of charge-control theory.
If switching times or, more generally, durations of dynamic transistor processes in terms of base charge only are required, then, given current or voltage control, the respective control quantity being known as a function of time, it is not necessary to formulate and solve the complete system of circuit equations. In the case of current control, one may solve Sparkes' equation, assuming different values for the switching time constant corresponding to the various operating regions. In the case of voltage control, an analogue equation may be solved, derived from a generalization of Sparkes' equation, which obviates the need for regional time constants. Both methods do not lend themselves well to the determination of dynamic transistor currents and voltages generally, except in the active region where base charge and output current are approximately proportional. [ABSTRACT FROM AUTHOR]

We present here a circuit designed to amplify a voltage of 10 V to 150 V, from d.c. to the Mc range. With this booster a low-voltage operational amplifier can be converted into a high-voltage one.
The booster has been used to construct a high-voltage analogue computer.
Most operational amplifiers have an output voltage ranging from -10 to + 10 V. In a regulating system, however, the need for a high voltage can occur. We cite, for example, that analogue computers operating at high voltages guarantee higher accuracies (G. A. Korn and T. M. Korn 1964).
The circuit described in this paper can amplify a voltage range of 10 V to a range of 150 V. With this stage, a low-voltage operational amplifier can be converted into a high-voltage one. [ABSTRACT FROM AUTHOR]