Doymamış Lineer Sürüklenme Hızlı TiO2 Memristörler İçin AC Güç Formülü, Tüm Memristörler İçin Küçük Sinyal AC Güç Formülü, ve Bu Formüllerin Bazı Uygulamaları

In 1971, Chua has claimed that there should have been one more fundamental circuit element called memristor. Memristor is nonlinear charge-dependent resistor. It dissipates power. No ideal memristor has been found yet. In 2008, a TiO2 thin-film memristive system which behaves as a memristor for some part of its operation has been found by a HP research team. The new circuit component can allow new types of analog and digital applications which are not possible with other fundamental circuit elements. This has resulted an emerging interest in memristor and memristive systems. In this paper, the average power formula of TiO2 memristor with linear dopant speed under AC excitation is derived. It is shown that a similar formula is applicable to all ideal memristors excited with a small signal AC source. The formulas derived here or similar formulas can be used to size the programmable memristor and memory circuits having AC waveforms.1971 yılında, Dr. Chua, memristör adı verilen, bir tane daha temel devre elemanı olması gerektiğini iddia etti.Memristör yüke bağımlı nonlinear bir dirençtir. Memristör güç tüketir. Henüz ideal bir memristör bulunmamıştır. 2008’de, bir HP araştırma takımı tarafından çalışma bölgesininin bir kısmında memristörmüş gibi davranan TiO2 ince-film bir memristif system bulunmuştur. Bu yeni devre elemanı diğer temel devre elemanları ile yapımı mümkün olmayan yeni tip analog ve sayısal uygulamalara izin verebilir. Bu ihtimal memristör ve memristif sistemler üzerine bir merak uyanmasını sağlamıştır. Bu makalede, AC gerilim altında, lineer sürüklenme hızlı TiO2 memristörün ortalama güç formülü türetilmiştir. Benzeri formülün küçük sinyal AC kaynağından beslenen tüm ideal memristörlere uygulanabilirliği gösterilmiştir. Burada türetilen formüller ya da benzeri formüller AC gerilime sahip programlanabilir memristör ve hafıza devrelerinin boyutlandırılmasında kullanılabilir

Logaritmik Memristanslı TiO2 Memristör

An ideal memristor, which was claimed to be the fourth fundamental element of circuit design by Dr. Chua in 1971, is a nonlinear resistor and its properties cannot be mimicked with linear time-invariant circuit elements. A thin-film which behaves as if a memristor has been declared found experimentally by a HP research team lead by Stanley Williams in 2008. A quite explicit model of the memristor has also been given by the team. The HP memristor resistance can be found by summing the resistances of the doped and undoped regions. Assuming the doped region length is proportional to memristor charge, which is the integration of memristor current, the doped region has a constant drift speed, and a constant memristor cross-section, the HP memristor resistance has a linear charge dependency till it saturates. In this paper, it is shown that a memristor with a logarithmic charge dependency can be made using the principles given by the team and making some modifications to memristor geometry.İdeal bir memristör, 1971 yılında Dr. Chua tarafından devre tasarımı için dördüncü temel devre elemanı olarak iddia edilen nonlinear bir dirençtir ve özellikleri lineer zamanla-değişmeyen devre elemanları tarafından taklit edilememektedir. Memristör olarak davranan bir ince-filmin bulunduğu, 2008 senesinde Stanley Williams tarafından yönetilen bir HP araştırma timi tarafından ilan edilmiştir. Bu memristörün oldukça anlaşılabilir bir modeli de bu tim tarafından verilmiştir. Bu HP memristör direnci katkılanmış ve katkılanmamış bölgelerin dirençlerini ekleyerek bulunabilir. Katkılanmış bölge uzunluğunun akımın integrali olan memristör yüküne orantılı olduğu, katkılanmış bölgenin sabit bir sürüklenme hızına sahip olduğu ve memristör kesiti sabit olarak kabul edilirek, HP memristör direncinin, doyma gerçekleşene kadar, lineer yük bağımlılığı vardır. Bu makalede, logaritmik yük bağımlılığı olan bir memristörün HP timi tarafından verilen prensipleri kullanarak ve memristör geometrisine bazı değişiklikler yapılarak yapılabileceği gösterilmiştir

Energy Consideration of a Capacitor Modelled Using Conformal Fractional-Order Derivative .

Fractional order circuit elements have become important parts of electronic circuits to model systems including supercapacitors, filters, and many more. The conformal fractional derivative (CFD), which is a new basic fractional derivative, has been recently used to model supercapacitors successfully. It is essential to know how electronic components behave under excitation with different types of voltage and current sources. A CFD capacitor is not a well-known element and its usage in circuits is barely examined in the literature. In this research, it is examined how to calculate the stored energy of a CFD capacitor with a series resistor supplied from a DC voltage source. The solutions given in this study may be used in circuits where supercapacitors are used

Spice model of current polarity-dependent piecewise linear window function for memristors

Memristor and memristive systems are nonlinear systems. It is important to model them accurately. There are different memristor models and most of the models make use of window functions. In literature, there are various window functions. Recently, a piecewise linear (PWL) window function is used to model a memristor and memristive systems. Such a memristor with a PWL window function lacks a SPICE model. Also, in literature, there is current polarity dependent window functions proposed for memristors to model polarity dependent drift speed within the thin-film memristors. In this study, an alternative current-polarity dependent PWL window function is suggested to model a memristor, a different PWL function one for each current polarity is used, its SPICE model is made in LTSpice and also its simulation results are given. Such a model can be used to model the polarity dependent drift speed within the thin-film memristors. © 2020, Gazi Universitesi. All rights reserved

A Conformal Fractional Derivative-based Leaky Integrate-and-Fire Neuron Model

Neuron model have been extensively studied and different models have been proposed. Nobel laureate Hodgkin-Huxley model is physiologically relevant and can demonstrate different neural behaviors, but it is mathematically complex. For this reason, simplified neuron models such as integrate-and-fire model and its derivatives are more popular in the literature to study neural populations. Lapicque’s integrate-and-fire model is proposed in 1907 and its leaky integrate-and-fire version is very popular due to its simplicity. In order to improve this simple model and capture different aspects of neurons, a variety of it have been proposed. Fractional order derivative-based neuron models are one of those varieties, which can show adaptation without necessitating additional differential equations. However, fractional-order derivatives could be computationally costly. Recently, a conformal fractional derivative (CFD) is suggested in literature. It is easy to understand and implement compared to the other methods. In this study, a CFD-based leaky integrate-and-fire neuron model is proposed. The model captures the adaptation in firing rate under sustained current injection. Results suggest that it could be used to easily and efficiently implement network models as well as to model different sensory afferents

On the equivalent ZIP parameter extraction of desktop computer cases and LCD monitors connected in parallel

Constant-impedance, constant-current and constant-power ZIP models of electrical loads arecommonly used in smart grid and residential load applications. Some of residential loads are ofnonlinear nature such as LCD monitors and computers. In this study, first, equivalent ZIP modelformulas of parallel-connected electrical loads are derived. Then, the ZIP models of an LCDmonitor, a computer case and the computer case and the monitor connected in parallel have beenobtained using experimental data and least-squares curve fitting method. Finally, the equivalentZIP model formulas are tested with the experimental data. It has been found that for the rectifiernonlinear loads with different ZIP parameters, the formulas do not give acceptable errors.Therefore, for rectifier nonlinear loads, the measurement-based approach for load modeling mustbe performed

Reconstructive sensing circuit for complementary resistive switches-based crossbar memories

Complementary resistive switches (CRSs) are suggested as an alternative to one-cell memristor memories to decrease leakage currents. However, their sensing is more difficult and complex than one-cell memristor memories. A method has been given for sensing their state using only DC voltages in the literature. However, in this strategy, sensing one of the logic states results in the destruction of the state and the destroyed state must be written again. To the best of our knowledge, a circuit with this sensing strategy does not exist in the literature yet. In this paper, such a circuit employing this method, which is able to read the CRS cells and able to reconstruct their data if the data are destroyed, is given. A new CRS model is also constructed in this paper and used for simulations to verify the operation of the circuit. The circuit is simulated using Simulink. We expect this circuit implementation to find use in the design and testing of CRS cells

Implementation of a Microcontroller-Based Chaotic Circuit of Lorenz Equations

Lorenz equations are commonly used in chaos education and studies. Simulation programs can be used to produce solutions of Lorenz equations and to examine its chaotic waveforms. However, sometimes a chaotic signal source can be needed. Such a circuit can be made using either analog or digital circuit components. Recently, a microcontroller-based circuit is suggested to obtain chaotic waveforms of Lorenz equations however only simulations are used to show proof of concept. Such a circuit needs experimental verification. In this paper, implementation and experimental verification of the microcontroller-based circuit which solves Lorenz equations in real-time and produces its chaotic waveforms are presented. Runge-Kutta method is used to solve the equation system. By using Proteus, the microcontroller-based chaotic circuit is simulated and designed. The presented design has been implemented using an Arduino Mega 2560 R3 microcontroller. The microcontroller sends the chaotic signals to the outputs of the circuit using digital-to-analog converters. The waveforms acquired experimentally from the implemented circuit match well with those obtained from Proteus simulations

Memristor-based series voltage regulators

Series linear voltage regulators are integrated circuits commonly used to make adjustable voltage sources. When used with potentiometers, these regulators are able to give adjustable voltage at the output. Memristor is a new nonlinear circuit element which came out in the last decade. It is able to provide electronically adjustable resistance. If a memristor is fed with a voltage over the threshold and it is not under saturation, its resistance also called memristance is dependent on the integration of its current, also called memristor charge. Memristor shows promise for different types and lots of digital and analog applications. In this paper, memristor-based series voltage regulator topologies are suggested and they are examined using parameters and simulations. Some design criteria have been given for the memristor-based series voltage regulators

Darbeli DC Sinterleme Sistemi Konteynerinin Soğumasına Yönelik Termal Devre Modeli

Pulse DC Sintering System (PDCS) is a cheap and quick way of producing different types of materials. After sintering of the sample, the cooling of the PDCS container is needed before taking it out. The sample production time is the sum of the sintering and the cooling time. Therefore, estimation of the sample cooling time must be made accurately to model sample production. Its container dimensions and the material, it is made of, determines its temperature during cooling. In this paper, a thermal circuit which models a pulse DC sintering system container during cooling is given. Its thermal circuit model is made assuming that some heat leaks from the steel container to the cooper bars, the copper bars and the container all have natural convection and also radiate heat to cool down. The thermal model is described with a set of nonlinear state-space equations. The state-space equations are solved numerically using Runge-Kutta 4 method. The time required to make the sample cool down to ambient temperature is calculated using simulations. The temperatures of the container and the copper bars of an PDCS system are measured to find the experimental cooling time. The results are compared. The PDCS thermal model is able to verify the experimental results. It has also been experimentally shown that the cooling time is not dependent on the sample type produced for the examined PDCS system. Such a model can be easily implemented in an engineering software which aims to model the sample production process of the PDCS system and can also be used for its optimization considering its physical parameters such as dimensions, electrical and mechanical constants etc.Darbe DC Sinterleme (PDCS), darbe genlik modülasyonlu doğru akım kullanarak farklı tipte malzemelerin ucuz ve hızlı biçimde üretilmesini sağlayan bir yöntemdir. Bu yöntemde numunenin sinterlenmesinden sonra, PDCS konteynerinin soğuması gerekir. Toplam üretim süresi sinterleme ve soğuma süresinin toplamıdır. Bu nedenle, numune üretim zamanını modellemek için numune soğuma süresinin belirlenmesi gereklidir. Kalıp boyutları ve üretilen malzeme, soğuma sırasındaki sıcaklığı belirler. Bu çalışmada, soğuma sırasındaki elektrik akım destekli sinterleme sistemi konteynerini modelleyen bir termal devre sunulmuştur. Isı devresi modeli, çelik konteynerden bakır baralara ısı transferi olduğu; bakır baralar ve konteynerin soğuma için doğal taşınıma sahip yayınım ile ısı yaydığı yaptığı kabulüyle oluşturulmuştur. Termal model, doğrusal olmayan durum-uzay denklemleri ile tanımlanmış ve denklemler numerik olarak Runge-Kutta 4 metodu kullanılarak çözülmüştür. Numunenin ortam sıcaklığına kadar soğuması için gereken süre simülasyonlar kullanılarak hesaplanmıştır. Elde edilen sonuçlar, konteyner ve bakır bara sıcaklıkları deneysel olarak ölçülen bir PDCS sisteminden elde edilen sonuçlarla karşılaştırılmıştır. Deneysel olarak, soğuma süresinin, incelenen PDCS sistemi için üretilen numune tipine bağlı olmadığı da gösterilmiştir. Böyle bir model, PDCS sisteminin numune üretim sürecini modellemeyi amaçlayan bir algoritmaya ve bunu gerçekleyecek donanıma kolayca uygulanabilir. Ayrıca önerilen model; boyutlar, elektriksel ve mekanik sabitler vb. fiziksel parametreleri dikkate alarak gerçekleştirilebilecek optimizasyon süreçlerinde kullanılabilir