Unijunction Research Articles

Bioinspired polydopamine coated nanopore nanofluidic unijunction transistor exhibiting negative differential resistance and ion current oscillation

Bioinspired polydopamine coated nanopore nanofluidic unijunction transistor exhibiting negative differential resistance and ion current oscillation

Dynamical Behavior of Two Coupled Two-Stroke Relaxation Oscillators

Starting from [J.-M. Ginoux et al., Torus breakdown in a uni junction memristor, Int. J. Bifurcation Chaos 28(10) (2018) 1850128; J.-M. Ginoux et al., Torus breakdown in a two-stroke relaxation memristor, Chaos Solitons Fractals 153 (2021) 111594], we define a model which describes the dynamical behavior of a class of two-stroke oscillators (i.e., nonlinear oscillators with two distinct phases per cycle). We highlight some properties of the model still not taken into account, like presence of a global bifurcation and bistability for some regions of the parameters space. We then extend the model to study two coupled two-stroke oscillators, where synchrony and anti-synchrony regimes appear as well as transient chaos and intermittency phenomena. We finally compare the theoretical results on synchrony regimes with the corresponding experimental data obtained from a circuit where two relaxation oscillators, based on the Unijunction Transistor (UJT) electronic component, are coupled together. The comparison shows a good qualitative agreement between the experiments and the theoretical results.

Study of the Operation and Output Waveforms of a Programmable Unijunction Transistor (PUT) Relaxation Oscillator

Study of the Operation and Output Waveforms of a Programmable Unijunction Transistor (PUT) Relaxation Oscillator

Збільшення чутливості та радіаційної стійкості сенсорів-перетворювачів температури на основі генераторів на одноперехідних транзисторах

The authors experimentally study the influence of temperature and radiation on the characteristics of generators based on a unijunction transistor (UJT). It is shown that when using a UJT-based generator as a sensor-converter with a frequency output, field-effect transistors are placed into the UJT emitter and base circuits to increase the dependence of frequency on temperature. Maximum sensitivity with direct dependence of frequency on temperature is achieved when a field-effect MOS transistor is connected to the emitter circuit UJT, and a field-effect transistor with a p-n junction is connected to the base circuit. The influence of radiation on the thermal sensitivity of generators is studied. The component transistors are irradiated with a flow of electrons, γ-quanta and neutrons. It is established that the irradiation of each transistor has a different effect on the initial frequency of the generator; it either decreases or increases. It is shown that it is possible to reduce the dependence of the output frequency on radiation using a transistor generator circuit with the opposite sign of the change in the generator frequency due to radiation. Maximum compensation for the effect of radiation on the output signal can be obtained by using a MOS transistor in the UJT emitter circuit, and a transistor with a p-n junction in the base circuit. The study establishes the limit values for fluxes of various radiations, after which the generator stops working.

Simple and highly efficient intermittent operation circuit for triboelectric nanogenerator toward wearable electronic applications

Triboelectric nanogenerator (TENG) is a promising power source toward the realization of self-powered wearable electronics. However, because of its pulsed output, a power management circuit, such as an intermittent operation circuit and AC–DC converter, is required to drive electronic devices. In this study, we propose a simple and highly efficient intermittent operation circuit composed of a programmable unijunction transistor. The energy transfer efficiency from the storage capacitor to the load reached 89%. We demonstrated that the intermittent circuit can be used to drive electronic devices such as stopwatches and wristwatches using the electricity generated by a carbon-nanotube-based stretchable TENG.

Controllability of the unijunction transistor based integrate-and-fire electronic spiking neuron

An integrate-and-fire (I&F) electronic neuron model is investigated theoretically and experimentally. The circuit comprises a unijunction transistor, a capacitor, and two resistors. It exhibits the following properties: (a) generates short spikes, (b) the steady state can be stabilized by a proportional or adaptive feedback, (c) high frequency action inhibits the spikes, (d) coupled units can synchronize with each other.

Study of gamma-ray effects on relaxation oscillator based on unijunction transistor

The object of this research is all the semiconductor unijunction transistor device (UJT) parameters that affect its operation as 1.67 kHz saw-tooth relaxation oscillator circuit under the influence of gamma-irradiation dose. Relaxation oscillators are widely used in function generators, electronic beepers, inverters, blinkers, and voltage-controlled oscillators. The properties of UJTs are like those of other semiconductor devices are greatly affect by irradiation. Its electrical characteristics and the output voltage waveforms of the relaxation oscillator circuit were investigated and plotted as a function of different gamma-dose levels. The type of semiconductor, the design of the device and the type of radiation are affected the magnitude of this change. Where, it is shown that increasing gamma dose up to 3.0 MGy leads, the peak voltage (VP) to be decreased from 3.71 Volts down to 2.9 Volts, while the valley voltage (VV) to be increases from 1.54 Volts up to 1.89 Volts, leading to a pronounced narrowing on the negative resistance region. As a result, both the output signal voltage amplitude and the frequency of the relaxation oscillator circuit were shown to be functions of the gamma-irradiation dose. Where, the initial values of the output signal voltage amplitude were reported to be 2.54 Volts decreased to the value of 2.13 Volts, while its frequency was 1.67 kHz increased up to 1.85 kHz, respectively, due to gamma-exposure levels up to 3.0 MGy using the GammaCell-220 (National Center for Radiation Research and Technology of Egypt).

Combined Semiconductor Injection Magnetic Field Sensors for Wireless Information Networks

The possibility of sensitivity increasing of magnetic field sensors by combining different types of sensitive elements in one sensor circuit is experimentally investigated. For this purpose, four new sensor constructions are proposed: based on bridge circuit, based on magnetotransistor in combination with magnetodiode or with second magnetotransistor and with frequency output. More thermostable and radiation-resistant sensor with 10 times greater sensitivity than in conventional two-diode bridge sensor is obtained with four polar magnetodiodes in bridge circuit, instead of two non-polar ones. Sensor constructions with two-collector magnetotransistors in combination with two polar magnetodiodes or one additional magnetotransistor are described. The sensitivity of such devices is 6 and 4 times higher compared to single-transistor sensors, while their temperature stability and radiation resistance increase. Relaxation generator circuit based on unijunction transistor is proposed as magnetic field sensor with frequency output. Inclusion of additional magnetodiode in generator circuit increases sensitivity by 2.3 times in comparison with single-transistor sensor and improves environmental stability. The described devices can be used as effective magnetic field sensors in wireless communication networks.

Torus Breakdown in a Uni Junction Memristor

Experimental study of a uni junction transistor (UJT) has enabled to show that this electronic component has the same features as the so-called “memristor”. So, we have used the memristor’s direct current (DC) [Formula: see text]–[Formula: see text] characteristic for modeling the UJT’s DC current–voltage characteristic. This has led us to confirm on the one hand, that the UJT is a memristor and, on the other hand, to propose a new four-dimensional autonomous dynamical system allowing to describe experimentally observed phenomena such as the transition from a limit cycle to torus breakdown.

Radiation Sensors Based on Field-Effect and Unijunction Transistors

The possibility of increasing the sensitivity of radiation sensors based on the field effect transistors is experimentally studied. A bridge circuit connecting two transistors with positive sign of the radiation sensitivity and two transistors with negative sign of the radiation sensitivity makes it possible to increase the dependence of the output voltage in the bridge diagonal on the absorbed radiation dose by an order of magnitude. The frequency sensor-converter of radiation designed on a unijunction transistor according to the circuit of the relaxation oscillator has the minimum number of individually attached components. The replacement of the resistor setting the current in the emitter circuit with a field-effect transistor sensitive to radiation increases the sensor sensitivity 5–10 times.

Synchronization of two memristively coupled van der Pol oscillators

The objective of this letter is to convey two essential principles of biological computing—synchronization and memory—in an electronic circuit with two van der Pol (vdP) oscillators coupled via a memristive device. The coupling was mediated by connecting the gate terminals of two programmable unijunction transistors through a resistance-capacitance network comprising an Ag-TiOx-Al memristive device. In the high resistance state the memristance was in the order of MΩ, which leads to two independent self-sustained oscillators characterized by the different frequencies f1 and f2 and no phase relation between the oscillations. Depending on the mediated pulse amplitude, the memristive device switched to the low resistance state after a few cycles and a frequency adaptation and phase locking were observed. The experimental results are underlined by theoretically considering a system of two coupled vdP equations. This experiment may pave the way to larger neuromorphic networks in which the coupling parameters (through memristive devices) can vary in time and strength and are able to remember the history of applied electrical potentials.

Study of the Ion Radiation Influence on the Parameters of Unijunction Transistors

The object of this report is study the influence of gamma quanta on some parameters of the unijunction transistors to synthesize radioisotope equipment.

PHOTODETECTOR ON THE BASE OF UNIJUNCTION AND FIELD-EFFECT PHOTOTRANSISTORS

Characteristics of the light converter with the frequency output on the base of the unijunction transistor were investigated. The field-effect transistor instead of resistor in the emitter circuit of the unijunction transistor was used for increase of linear dependence of the frequency for the light stream. Expansion of the photosensitivity spectrum into the infrared region may be arrived if the base of the field-effect transistor contains the dopants which made the deep level in the band gap of silicon.

Frequency-output sensors-transducers based on unijunction transistors

The experimental characteristics of sensors of nonelectrical quantities (temperature, magnetic field, light, and pressure) based on a unijunction transistor (UJT), which is a component of a relaxation oscillator, have been investigated. Designs of measuring sensors-transducers in which the UJT and other circuit elements serve as components sensitive to external action are presented. It is shown that, if the output parameter of the sensors is the oscillation frequency that is determined by the magnitude of the corresponding action, insertion of additional sensing elements into the circuit makes it possible to significantly increase the efficiency of the sensors-transducers.

ANALOG CONVERTER OF LIGHT ON THE BASE OF UNIJUNCTION TRANSISTOR

The principle of action of the analog converter of light based on the base of unijunction transistor oscillator with current driving element and the capacitor in the emitter circuit is shown. The output parameter is the frequency of oscillation as a function of light intensity. Maximum sensitivity is achieved when the element is used as a current driving bipolar phototransistor and the capacitance decreases with decreasing voltage.

Industrial Research in Microcircuitry at RCA: The Early Years, 1953–1963

RCA had an established research capability and transistor manufacturing facility in place during the early years of the semiconductor industry. Its early microcircuit research-including Torkel Wallmark's work using the bipolar unijunction transistor in the late 1950s, Paul Weimer's thin-film transistor, and Steve Hofstein's metal-oxide silicon transistor-led to RCA's pioneering effort in the production of complementary (CMOS) silicon integrated circuits in the late 1960s and 1970s.

Base resistance in Si unijunction transistor irradiated by 60Co γ-radiation

The change of base resistance in Si-UJT under irradiation of 60Co γ-ray is provided. Through multipoint measurement and real-time monitoring, it was shown that the base resistance decreased immediately and then increased slowly. Compared with domestic and foreign related research results, this proves that the displacement effect is the main effect of base resistance in Si-UJT irradiated by 60Co γ-ray, but it lags behind the ionization effect from microanalysis of the interaction between γ-ray and Si material. This is very important for the radiation hardened research.

Coherence resonance in a unijunction transistor relaxation oscillator

The phenomenon of coherence resonance is investigated in an unijunction transistor relaxation oscillator and quantified by estimating the normal variance (NV). Depending on the measuring points, two types of NV curves have been obtained. We have observed that the degradations in coherency at higher noise amplitudes in our system is probably the result of direct interference of coherent oscillations and the stochastic perturbation. Degradation of coherency may be minimal if this direct interference of noise and coherent oscillations is eliminated.

SENSOR OF TEMPERATURE ON THE BASIS OF UNIJUNCTION AND FIELD TRANSISTORS AT THE RADIATION-DAMAGE

The chart of sensor of temperature is developed on the basis of generator on an unijunction transistor with two current-lead fields transistors, frequency of generation of which linear grows with the increase of temperature. Influence of radiation is experimentally investigational on his capacity.

Calcium-Induced Voltage Gating in Single Conical Nanopores

We examine time signals of ion current through single conically shaped nanopores in the presence of sub-millimolar concentrations of calcium ions. We show that calcium induces voltage-dependent ion current fluctuations in time in addition to the previously reported negative incremental resistance (Nano Lett. 2006, 6, 473-477). These current fluctuations occur on the millisecond time scale at voltages at which the effect of negative incremental resistance was observed. We explain the fluctuations as results of transient binding of calcium ions to carboxyl groups on the pore walls that cause transient changes in electric potential inside a conical nanopore. We support this explanation by recordings of ion current in the presence of manganese ions that bind to carboxyl groups 3 orders of magnitude more tightly than calcium ions. The system of a single conical nanopore with calcium ions is compared to a semiconductor device of a unijunction transistor in electronic circuits. A unijunction transistor also exhibits negative incremental resistance and current instabilities.