• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권7호
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• pp.331-338
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• 2002

An inverter-fed induction is driven by a harmonic voltage source so that it is necessary to be analysed by time-stepping F.E.M. But it takes so long time that disadvantageous to design. This paper presents a simple analysis method for inverter-fed induction motor using FEM and harmonic equivalent circuit. First, the rotor bar resistance and the leakage reactance are determinated by FEA for 1 slot region in rotor to consider the skin effect and the saturation. Secondly, the characteristic of the motor is analyzed by the harmonic equivalent circuits consisting of the obtained parameters from the FEA. This method is carried out to analyze an induction motor driven by the sinusoidal voltage and the inverter. The results are verified by comparing with those of the time-step F.E.A and the experiment.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2003년도 추계학술대회 발표 논문집
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• pp.182-185
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• 2003

We have suggested an equivalent circuit model for switching performance of bipolar spin transistor composed of a nonmagnetic metal film (N) sandwiched between two ferromagnetic metal films (F1 and F2). The 'ON' or 'OFF' operation of this equivalent circuit model is simulated by depending on the orientation of the magnetization of F1 and F2 rather than the strength of the external magnetic filed. Changing the coupling coefficient, turn number of two inductances, (L1:L2) like a transformer, and parallel variable resistance R4 connected to L2 at the collector region, we can explain the magnetic characteristics and the dependence of magneto resistance ratio on the orientation of spin-polarized electrons.

• 전자공학회논문지B
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• 제32B권11호
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• pp.1374-1382
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• 1995

In TFT-LCDs, as the display size area becomes larger, and the resolution higher, we have to consider the image degradation effects due to the incorporation of the TFT-LCD parameters such as the data-line resistance, the common electrode resistance, the data-line to common parasitic capacitance, and the output characteristics of driver ICs. One of the degradation effects is crosstalk resulting from the coupling between the source bus-line and common electrode. Since a source signal which represents a large number of display data is supposed to vary frequently, the common signal level is affected through the coupling effect, resulting in the degradation of nearby pixel drive signals. Therefore, we proposed a method to compensate for this source-common electrode coupling effect, we also designed and experimented the feasibility of our crosstalk compensation circuit in the actual TFT-LCD. We saw that the newly designed compensation circuit greatly reduced the crosstalk in display pattern image.

• Journal of Electrochemical Science and Technology
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• 제13권3호
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• pp.369-376
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• 2022

In this study, the stability of an anion exchange membrane water electrolyzer (AEMWE) cell was evaluated in an on-off cycling operation with respect to an applied electric bias, i.e., a current density of 500 mA cm^-2, and an open circuit. The ohmic and polarization resistances of the system were monitored during operation (~800 h) using electrochemical impedance spectra. Specific consideration was given to the ohmic resistance of the cell, especially that of the membrane under on-off cycling conditions, by consistently feeding the cell with KOH solution. Owing to an excess feed solution, a momentary increase in the polarization resistance was observed immediately after the open-circuit. The excess feed solution was mostly recovered by subjecting the cell to the applied electric bias. Stability tests on the AEMWE cell under on-off cycling with continuous feeding even under an open circuit can guarantee long-term stability by avoiding an irreversible increase in ohmic and polarization resistances.

• 대한전자공학회논문지SD
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• 제38권8호
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• pp.1-12
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• 2001

본 연구에서는 MFSFET (Metal-Ferroelectric-Semiconductor FET) 소자의 모델링을 바탕으로 adaptive learning 회로를 설계하고, 그 수치적인 결과를 분석하였다. Adaptive learning 회로에서 출력주파수는 MFSFET 소자의 소스-드레인 저항과 캐패시턴스에 반비례하는 특성을 보여주었다. Short pulse 수에 따른 포화드레인 전류곡선은 강유전체의 분극반전 특성과 유사함을 확인할 수 있었고, 이는 강유전체 분극이 MFSFET 소자의 드레인 전류조절에 핵심적인 요소로 작용한다는 사실을 의미한다. 다음으로 MFSFET 소자의 드레인 전류조절에 핵심적인 요소로 작용한다는 사실을 의미한다. 다음으로 MFSFET 소자의 소스-드레인 저항으로부터 dimensionality factor 와 adaptive learning 회로의 펄스 수에 따른 출력주파수 변화를 분석하였다. 이 특성으로부터, adaptive learning 회로의 주파수변조 특성 즉, 입력펄스의 진행에 따라 출력펄스의 점진적인 주파수 변화를 의미하는 adaptive learning 특성을 명화하게 확인할 수 있었고, 뉴럴 네트워크에서 본 회로가 뉴런의 시넵스 부분에 효과적으로 사용될 수 있음을 입증하였다.

• 조명전기설비학회논문지
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• 제26권7호
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• pp.45-51
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• 2012

In this paper, the wireless power transfer system using the magnetic resonance was designed and the effect of resonant coil radius and load resistance to this system was analyzed by the circuit analysis method. As a result, the calculated transmitted-power is similar to measured one, and the coil size has a small effect to the coupling coefficients in the resonant frequency band. In addition, the fact that the calculated transmitted-power according to the source frequency is similar to measured one confirms that the circuit analysis methode in this paper is valid. The input side transmission efficiency ${\eta}_i$ including only the loss in the power transfer circuit is almost 90[%] with the large coil in the 10[cm] transfer distance, and 65[%] with the small coil in 1[cm]. The source side transmission efficiency ${\eta}_s$ is 30~40[%] at both coil when load resistance below 4.7[${\Omega}$] has been connected. Considering that the maximum ${\eta}_s$ is 50[%], this is valid in the practical applications.

• 한국정밀공학회지
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• 제27권10호
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• pp.23-28
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• 2010

Resistance trimming and cutting processes of printed circuit board by making use of high power UV laser with nano-second pulse width have been proposed and investigated experimentally. Also laser-based application system with high flexibility and complex has been designed and adopted power controller, auto beam size control, auto-focusing and control program developed for ourselves. The function of each module shows that they can be reliable for industrial equipments. Resistance trimming method used a plunge and double cut process with $20{\mu}m$ spot size beam. Results show that double cut process is more effective to control resistance trimming in precision than plunge cut process.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 제6회 학술대회 논문집 일렉트렛트 및 응용기술연구회
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• pp.5-8
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• 2004

We have investigated equivalent-circuit analysis of organic light-emitting diodes using frequency-dependent response of $ITO/Alq_3(60nm)/Al$ device at two different bias voltages. Complex impedance Z of the device was measured in the frequency range of 40Hz~1MHz. A Cole-Cole plot shows that there are two dielectric relaxations at the bias below turn-on voltage, and one relaxation at the bias above turn-on voltage. We are able to interpret the frequency-dependent response in terms of equivalent-circuit model of contact resistance $R_s$ in series with parallel combination of resistance $R_p$ and capacitance $C_p$. We have obtained contact resistance $R_s$ around $90{\Omega}$, mainly from the ITO anode.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.438-439
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• 2006

We have used ITO/$Alq_3$/Al structure to study complex impedance in $Alq_3$ based organic light emitting diode. Equivalent circuit was analyzed in a device structure of ITO/$Alq_3$/Al by varying the thickness of $Alq_3$ layer from 60 to 400nm. The impedance results can be fitted using equivalent circuit model of parallel combination resistance $R_p$ and capacitance $C_p$ with a small series resistance $R_s$.

• 전력전자학회논문지
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• 제24권5호
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• pp.365-371
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• 2019

This study shows the feasibility of the parameter of the 1st RC parallel equivalent circuit as a factor of the heat generation of lithium-ion cell. The internal resistance of a lithium-ion cell consists of ohmic and polarization resistances. The internal resistances at various SOCs of the lithium-ion cell are obtained via an electrical characteristic test. The internal resistance is inversely obtained through the amount of heat generated during the experiment. By comparing the resistances obtained using the two methods, the summation of ohmic and polarization resistances is identified as the heating factor of lithium-ion battery. Finally, the amounts of heat generated from the 2C, 3C, and 4C-rate discharge experiments and the COMSOL multiphysics simulation using the summation of ohmic and polarization resistances as the heating parameter are compared. The comparison shows the feasibility of the electrical parameters of the 1st RC parallel equivalent circuit as the heating factor.