• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1561-1564
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• 2004

A CMOS-based Electronically Tunable Capacitance Multipliers, which can be magnified the value of a grounded unit capacitance, is presented in this article. The multiplication factor is varied by the ratio of the bias currents. The proposed circuit is simple, small in size and suitable for implementing in standard CMOS process. PSPICE simulation results demonstrating the characteristics of the proposed circuit are included.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.102-104
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• 1996

The fabrication and analytical expression for the temperature dependent capacitance characteristics of inverted staggered hydrogenerated amorphous silicon thin film transistors(a-si :H TFT) from 303k to 363k were presented. The results show that the experimental capacitance-voltage characteristics at several temperatures are easily measured. Capacitance increased exponentially by gate voltage increase and decreased by temperature increase. C/C(max) ratio decreased at higher temperature, C/C(min) ratio increased at higher temperature.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.395-398
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• 1999

In ac PDP(plasma Display Panel), the discharge characteristics is very important to display clear images. In this paper, we have studied the measurement of voltage transfer curves which show the discharge characteristics in AC PDP. The change of the effective wall capacitance during a discharge is also studied. These depend on lateral spreading of charge distribution and the strength of the discharge. As a parameter of the frequency, we observed the effects of the frequency in voltage transfer curves and in effective wall capacitance changes. As frequency increases, minimum sustain voltage and firing voltage decrease. In upper region of gap voltage the chance of the effective wall capacitance is independent of frequency.

• 전기학회논문지
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• 제67권4호
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• pp.522-530
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• 2018

This study proposes the mitigation method of shaft voltage by varying the parasitic capacitance. First, the shaft voltage explained. Second, the parasitic capacitances causing shaft voltage are analyzed respect to geometry of motor and windings. Then, the equivalent circuit is established to obtain the shaft voltage and output torque characteristic and develope appropriate motor structure. Finally, simulation and experiment are conducted to verify that modified motor suppress the shaft voltage. This novel model does not require additional hardware.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권3호
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• pp.134-141
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• 2006

A potential transformer(PT) has ratio error and phase angle error. Precise measurement of the errors of PT can be achieved using high voltage capacitance bridge, high voltage capacitor and low voltage capacitor. The uncertainty for this method is evaluated and found to be $20{\times}10^{-6}$ in both ratio error and phase angle error. The values measured for PT using the method are well consistent with the those measured for same PT in NMIA(National Measurement Institute of Australia) within the corresponding uncertainty.

• 한국전기전자재료학회논문지
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• 제36권2호
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• pp.129-135
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• 2023

An analytical threshold voltage model is presented to observe the change in threshold voltage shift ΔV_th of a junctionless double gate MOSFET using ferroelectric-metal-SiO₂ as a gate oxide film. The negative capacitance transistors using ferroelectric have the characteristics of increasing on-current and lowering off-current. The change in the threshold voltage of the transistor affects the power dissipation. Therefore, the change in the threshold voltage as a function of theferroelectric thickness is analyzed. The presented threshold voltage model is in a good agreement with the results of TCAD. As a results of our analysis using this analytical threshold voltage model, the change in the threshold voltage with respect to the change in the ferroelectric thickness showed that the threshold voltage increased with the increase of the absolute value of charges in the employed ferroelectric. This suggests that it is possible to obtain an optimum ferroelectric thickness at which the threshold voltage shift becomes 0 V by the voltage across the ferroelectric even when the channel length is reduced. It was also found that the ferroelectric thickness increased as the silicon thickness increased when the channel length was less than 30 nm, but the ferroelectric thickness decreased as the silicon thickness increased when the channel length was 30 nm or more in order to satisfy ΔV_th=0.

• Journal of Power Electronics
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• 제13권3호
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• pp.329-338
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• 2013

In this paper, the charging characteristics of series resonant type high voltage capacitor chargers considering the transformer stray capacitance have been studied. The principles of operation for the four operational modes and the mode changes for the four different switching frequency sections are explained and analyzed in the range of switching frequency below the resonant frequency. It is confirmed that the average charging currents derived from the above analysis results have non-linear characteristics in each of the four modes. The resonant current, resonant voltage, charging current, and charging time of this capacitor charger as variations of the switching frequency, series parallel capacitance ratio ($k=C_p/C_s$), and output voltage are calculated. From the calculation results, the advantages and disadvantages arising from the parallel connection of this stray capacitance are described. Some methods to minimize charging time of this capacitor charger are suggested. In addition, the results of a comparative test using two transformers whose stray capacitances are different are described. A 1.8 kJ/s prototype capacitor charger is assembled with a TI28335 DSP controller and a 40 kJ, 7 kV capacitor. The analysis results are verified by the experiment.

• 전기화학회지
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• 제6권2호
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• pp.158-160
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• 2003

We have reported to make nanostructured cobalt oxide electrode that have large capacitance over than 400 F/g (specific capacitance) and good cycleability. But, it had serious demerits of low voltage range under 0.5 V and low power density. Therefore, we need to increase voltage range of cobalt oxide electrode. We report here on the electrochemical properties of sol-gel-derived nanoparticulate cobalt xerogel in 1M KOH solution and aqueous polymeric gel electrolyte. In solution electrolyte, cobalt oxide electrode had over 250 F/g capacitance consisted of EDLC and pseudocapacitance. In gel electrolyte, cobalt oxide electrode had around 100 F/g capacitance. This capacitance was only electric double layer capacitance of active surface area. In solution electrolyte, potassium ion as working ion reacted with both of layers easily. However, In gel electrolyte, reacted with only surface-active layer. Itis very hard to reach resistive layer. So, we have studied on pretreatment of electrode to contain working ions easily. We'll report more details.

• 한국생산제조학회지
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• 제25권4호
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• pp.307-311
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• 2016

Several types of supercapacitors have been developed for energy storage systems. Among them, the hybrid type has advantages such as a large capacitance per weight compared with the electric double-layer capacitator type. In this study, constant current charging and discharging tests were conducted for recently developed hybrid-type supercapacitors. Based on the experimental results, the capacitance and equivalent series resistance were obtained. The capacitance was larger than the designed capacitance at a low current but became small at a high current. In addition, the capacitance depended on the cell voltage. These results can be used to design an energy storage system.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권2호
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• pp.130-133
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• 2011

A comparative study of two capacitance methods to measure the effective channel length in deep-submicron MOSFETs has been made in detail. Since the reduction of the overlap capacitance in the accumulation region is smaller than the addition of the inner fringe capacitance at zero gate voltage, the capacitance method removing the parasitic capacitance in the accumulation region extracts a more accurate effective channel length than the method removing that at zero gate voltage.