• 한국응용과학기술학회지
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• 제24권4호
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• pp.377-382
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• 2007

We designed capacitance sensor in order to examine characteristics of W/O type emulsified fuel, so it concluded the following conclusions. The capacitance value of emulsified fuel, using with capacitance sensor, increases as water content increases due to the coalescence. When surfactant increases, the capacitance value decreases, the condition of W/O type emulsified fuel was maintained stably. There was revealed the capacitance value difference of W/O type emulsified fuel in in according to water content. We checked the phase separation of emulsified fuel with the capacitance value difference. The surfactant(HLB=5.4) had better stable condition than surfactant(HLB=4.3). Also, we confirmed that two mixture surfactants were better than one surfactant.

• 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.

• 전기학회논문지
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• 제61권6호
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• pp.817-820
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• 2012

We studied p-type capacitance characteristics of ZnO thin-film transistors (TFT's), grown by metal organic chemical vapor deposition (MOCVD). We compared two ZnO TFT's: one grown at $450^{\circ}C$ and the other grown at $350^{\circ}C$. ZnO grown at $450^{\circ}C$ showed smooth capacitance profile with electron density of $1.5{\times}10^{20}cm^{-3}$. In contrast, ZnO grown at $350^{\circ}C$ showed a capacitance jump when gate voltage was changed to negative voltages. Current-voltage characteristics measured in the two samples did not show much difference. We explain that the capacitance jump is related to p-type ZnO layer formed at the $SiO_2$ interface. Current-voltage and capacitance-voltage data support that p-type characteristics are observed only when background electron density is very low.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1084-1087
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• 2002

The guard-ring type 3-terminal parallel plate electrodes proposed by ASTM D 150-81 and IEC 250 have been widely used for measurement of dielectric constants of solid dielectrics. However the method using this electrodes causes many uncertainty associated with the measurement errors of the diameter of the guarded electrode. the gap between guarded and guard-ring electrode. the distance of two active electrodes(the thickness of specimen), the roughness and contamination of surface of electrode and specimen. close adherence grade of electrode and specimen. In this paper. a new electrode system of cross capacitance type based on Thompson-Lampard theorem is designed and is employed for the measurement of dielectric constant. The results of simulation of guard-ring electrode and cross capacitance electrode using FEM program show that distance measurement between two electrodes in guard-ring electrode produces large uncertainty. on the other hand this effect in cross capacitance electrode is negligible. Furthermore. the air gap effects in the cross capacitance electrode is 5.6 times less sensitive than that in guard-ring electrode by assuming air gap of $50{\mu}m$.

• 전력전자학회논문지
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• 제20권2호
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• pp.137-143
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• 2015

This paper presents the intra capacitance modeling based on the winding method and section bobbin for CM choke capable of EMI attenuation of broad bands from lower to higher frequency bands and high frequency type common-mode choke capable of EMI attenuation of high frequency band used in the EMI Block of LED-TV SMPS. The case of high frequency type CM choke can be explained by the parasitic capacitance of three types of CM choke. The winding method of section bobbin type is smaller than the others. The first resonant frequency of the proposed CM choke tends to increase as the parasitic capacitance becomes small and its impedance characteristics improved performance as the first resonant frequency increases. The CM chokes of the proposed section bobbin type shows that in the future, the method may have practical use in LED/LCD-TV SMPS and in several applications, such as LED lighting, adapters, and so on.

• Journal of information and communication convergence engineering
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• 제19권4호
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• pp.263-268
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• 2021

Although the compact capacitance model of point tunneling types of tunneling field-effect transistors (TFET) has been proposed, those of line tunneling types of TFETs have not been reported. In this study, a compact capacitance model of an L-shaped TFET (LTFET), a line tunneling type of TFET, is proposed using the previously developed surface potentials and current models of P- and L-type LTFETs. The Verilog-A LTFET model for simulation program with integrated circuit emphasis (SPICE) was also developed to verify the validation of the compact LTFET model including the capacitance model. The SPICE simulation results using the Verilog-A LTFET were compared to those obtained using a technology computer-aided-design (TCAD) device simulator. The current-voltage characteristics and capacitance-voltage characteristics of N and P-LTFETs were consistent for all operational bias. The voltage transfer characteristics and transient response of the inverter circuit comprising N and P-LTFETs in series were verified with the TCAD mixed-mode simulation results.

• 한국분말재료학회지
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• 제30권4호
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• pp.310-317
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• 2023

Small-film-type ion sensors are garnering considerable interest in the fields of wearable healthcare and home-based monitoring systems. The performance of these sensors primarily relies on electrode capacitance, often employing nanocomposite materials composed of nano- and sub-micrometer particles. Traditional techniques for enhancing capacitance involve the creation of nanoparticles on film electrodes, which require cost-intensive and complex chemical synthesis processes, followed by additional coating optimization. In this study, we introduce a simple one-step electrochemical method for fabricating gold nanoparticles on a carbon nanotube (Au NP-CNT) electrode surface through cyclic voltammetry deposition. Furthermore, we assess the improvement in capacitance by distinguishing between the electrical double-layer capacitance and diffusion-controlled capacitance, thereby clarifying the principles underpinning the material design. The Au NP-CNT electrode maintains its stability and sensitivity for up to 50 d, signifying its potential for advanced ion sensing. Additionally, integration with a mobile wireless data system highlights the versatility of the sensor for health applications.

• 대한전자공학회논문지TE
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• 제42권4호
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• pp.1-6
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• 2005

최근 저항이나 캐패시터와 같은 수동소자를 PCB의 내층에 제조하는 임베디드 패시브 기술이 고성능의 IT 제품을 제조하는데 사용되고 있다. 그런데 임베디드 캐패시터는 정전용량 밀도가 낮아 회로소자로서의 전반적인 응용에 한계가 있다. 본 논문에서는 이러한 한계를 극복하기 위하여 wrinkle형의 전극과 유전체 층을 가진 새로운 임베디드 캐패시터를 제안하였다. FEM 기법을 사용하여 wrinkle형 임베디드 캐패시터의 정전용량 밀도를 평가하였다. Wrinkle형 임베디드 캐패시터는 기존의 평면형 임베디드 캐패시터에 비하여 25.6%$\sim$39.6% 정도 큰 정전용량 밀도를 나타내었다. 특히, thin film형 임베디드 캐패시터에 wrinkle 구조를 적용할 때 정전용량 밀도가 보다 많이 향상되었다.

• 조명전기설비학회논문지
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• 제28권3호
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• pp.32-43
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• 2014

This paper presents the intra capacitance modeling according to the winding method, section bobbin and coil structure for hybrid choke coil capable of the EMI attenuation of broad bands from lower frequency bands to higher frequency bands and high frequency type common-mode choke coil capable of the EMI attenuation of high frequency band used in the EMI Block of LED-TV SMPS. In case of high frequency type CM choke coil, it can be explained the parasitic capacitance of A type and section bobbin type winding methods among them is much smaller than the other. The first resonant frequency of the proposed CM choke coil tends to increase as the parasitic capacitance becomes small and its impedance characteristics also show improved performance as the first resonant frequency increases. In case of hybrid choke coil using rectangular copper wire, it has investigated its parasitic capacitance compared to CM choke coil of conventional toroidal type becomes small. Also it has confirmed through the experiment results that CE margin and RE margin in frequency bands 0.5MHz to 5MHz and 30MHz to 200MHz are respectively 10dB and 15dB greater than that of conventional type in case of one stage EMI filter structure adopting hybrid choke coil compared to two stage EMI Filter structure using two of each CM choke coil used in the lower and higher frequency bands or two of CM choke coil used in only the lower frequency bands. In the future, the hybrid choke coil and CM choke coil of high frequency type show it can be practically used in not only LED/LCD-TV SMPS but also several applications such as LED Lighting, Laptop Adapter, Server Power Supply and so on.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.291-295
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• 1996

This paper discusses several design factors of a capacitance displacement sensor with a numerical method and several experiments and describes guide lines of the design of this type sensor. We introduce the charge density method for the analysis of this type sensor, which has feasible accuracy and efficiency. The analysis of this type sensor with the charge density method agrees with displacement sensitivity experiments of a circular plate capacitance sensor with the sensor amp based In the charge transfer principle.