In recent years, much attention has been given to various printing techniques to produce low-cost electronic ingredients and equipment. Inkjet printing is one of the most promising methods for printing circuit ingredients in one step almost on any substrates. In this study, the inkjet printing technique was employed for chemical deposition of silver nanoparticles by ejecting aqueous solutions of silver nitrate as metal salt and ascorbic acid as reducing agent on flexible substrates such as paper and fabric. Inkjet-deposited silver patterns were used as Capacitors in electrical circuits and their performance was tested. Different values of capacitance were gained by a simple change in the size and shape of the printed capacitor. The highest capacitance values gained on an inkjet-deposited capacitor (a parallel plate capacitor with 1 cm2 overlapped area) on paper and fabric were 85. 1 and 1370 pF, respectively. Inkjet-printed Capacitors (interdigital Capacitors with six fingers) could display a capacitance around 20 and 6 pF on paper and fabric, respectively. Levels of capacitance achieved by the new inkjet deposition technique can successfully match and exceed the capacitance levels of conventional Capacitors produced using current multi-step fabricating methods.

This paper presents a comprehensive case study on electro-mechanical analysis of MEMS1 variable Capacitors. Using the fundamental mechanical and electrical equations, static and dynamic behaviors of the device are studied. The analysis is done for three different modes, namely: dc (static mode), small signal ac and large signal regime. A complete set of equations defining dynamic behavior of the MEMS, and an ac small signal equivalent circuit are presented. The mathematical models are defined and examined by the Mat lab Simulink and a complete set of simulation results is reported for various cases separately. The results of this study would be useful in design and analysis of the MEMS based circuits which have some kind of mechanical dynamic action. Some examples of such devices may include VCO2s, frequency modulators, tunable filters and parametric effect circuits.

In this paper, an analog Low pass Gm/C filter with tunable cutoff frequency from 1.5 to 5.5 MHZ is designed. This filter is used in adjustable - bandwidth antialiasing video filters. Cut off frequency tuning is done using depletion - mode substrate - biased MOS gate Capacitors. A fifth order elliptic filter is designed by cascade synthesis method. The filter consists of a first order and two notch Biquadratic fully differential Gm/C sections. The cutoff frequency of each section can be tuned independently by substrate bias voltage of Mos gate Capacitors.The Hspice simulation results show the efficiency of this tuning method for tunable video filters.

Nowadays, because of the need to decrease fuel consumption and greenhouse gas emissions and also their capability of exchanging power with the grid and regulating the frequency and voltage of the grid at different times of the day, electric vehicles are used more than before all across the world. It is highly important to pay attention to the efficiency, and decrease in the weight and volume of these vehicles. The chargers of these vehicles can form a huge portion of the volume and weight of these vehicles. DC link Capacitors are the large parts of these chargers. Based on the mathematical modeling and relationships of the system, this study focuses on the optimal capacitor value based on the required specifications. In the model presented in this article, the optimal value of DC link capacitor is estimated by taking into account instantaneous input power of the charger, the relationship of the energy balance between the grid and the DC link capacitor, and application of Taylor series to the output of the relationship. The optimal DC link capacitor value is estimated through calculating the DC link voltage, and measuring the exchanged energy and changes of DC Link Voltage during charging. The most considerable advantages of the proposed model are the simplicity of its design together with the minimum weight and volume of the charger due to its low capacitor value. SIMULINK environment of MATLAB software was used to evaluate the proposed model. The simulation results show that the model was successful.

In this research work, laser scribed technique has been regarded to synthesize graphene on the surface of a DVD and manufacture graphene super Capacitors. For this purpose, first, by Hummers method, graphite was converted to graphene oxide (GO) in an acidic environment containing Sodium nitrate, Potassium permanganate and sulfuric acid. Centrifuges and ultrasonic devices were utilized for the homogenization of graphene oxide solution. GO homogeneous solution was applied on the surface of specific DVDs and the set was dried at room temperature. For GO reduction and transform it into graphene, a suitable laser, with programming of super capacitor particular pattern was used. By applying an energy with the amount of resonance frequency of graphene and oxygen bond, the laser broke the connection and the reduction action and reaching to graphene was done. In this study, the process of graphene synthesis and applying the super capacitor specific pattern were carried out in single step that is the biggest advantage of laser scribed graphene (LSG) method. In present study, TEM was utilized to examine the layered structure of GO, SEM was used for microstructural studies, two tests of cyclic voltammetry (CV) and galvanostatic charge/discharge (CC) were applied to study the performance and power of energy storage in super Capacitors, the XPS was used to investigate elements present in the layer applied on DVD, and the Raman spectroscopy was applied to investigate the quality of prepared graphene through studying G and D peaks.