• 한국초전도ㆍ저온공학회논문지
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• 제16권2호
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• pp.29-32
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• 2014

The critical current, $I_c$ of HTS superconducting tapes can be measured by transport or contactless method. Practically, the transport method using the four-probe method is the most common. In this study, a simple test procedure by clipping the voltage lead taps have been introduced instead of soldering which reduces time and effort and thereby achieving a much faster measurement of $I_c$. When using a pair of iron clips, $I_c$ value decreased as compared with the measured one by standard method using soldered voltage taps and varies with the width of the clipped specimen part. However, when using a pure Cu clip, both by clipping and by soldering voltage taps give a comparable result and $I_c$ measured are equal and close to the samples specification. As a result, material to be used as voltage clip should be considered and should not influence the potential voltage between the leads during $I_c$ measurement. Furthermore, the simulation result of magnetic flux during $I_c$ measurement test showed that the decrease of $I_c$ observed in the experiment is due to the magnetic flux density, $B_y$ produced at the clipped part of the sample by the operating current with iron clips attached to the sample.

• 한국항행학회논문지
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• 제23권4호
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• pp.316-321
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• 2019

본 논문에서는 정전류(constant current) 원리를 적용하여 각종 전기재료의 특정 대역 고정밀 임피던스 측정이 가능한 임피던스 측정 시스템을 마이크로프로세서를 사용하여 개발한다. 본 측정 시스템 보드에는 임피던스 측정장치를 포함하여 외부장치에서 디지털 데이터 취득을 위한 인터페이스 장치를 갖추고 있으며, 이와 같은 임베디드 보드에서 실행되는 펌웨어 프로그램으로 시스템 소프트웨어를 작성한다. 그리고 15-비트 ADC (analog-to digital converter)를 사용하여 특정 대역의 정밀 임피던스를 1/32768 정밀도로 측정하여 소수점 5자리까지 연산하여 출력할 수 있으며, 디지털 데이터를 관리하기 위해 개발된 측정장치와 일반 컴퓨터의 USB 인터페이스를 통해 데이터를 전송하여, 여타 측정 장비들 보다 범용적이고 사용이 용이한 인터페이스가 가능한 통신기능을 탑재한 임피던스 측정시스템을 개발하고 그 정밀도를 측정하여 검증한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.352-355
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• 2001

In this paper, we proposed measurement error reduction technique for the semiconductor device DC characteristic measurement system. Implemented system is composed of 4 SMUs, 2 VSUs, and 2 VMUs. Various efforts in hardware and software have been made to reduce the measurement errors due to the leakage current in measurement circuits. Internal and external sources of errors in measurement system especially in pA range measurement have been identified and removed. Experimental results show that the implemented system can be measure the DC characteristic of semiconductor devices in pA level.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.74-76
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• 1996

This measurement method described in this paper can be applied for the accurate determination for voltage and current of inverter with harmonics. The method, based on a thermal principle, relies on adaptation of the measurement thermal e.m.f to signal of inverter and comparison of AC to DC signals. The performance of the measurement system is compared with calculated results and reference power system. With this method, an accuracy of 0.1% can be achieved.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1920-1923
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• 1991

An online RF power measurement is needed for the full-bridged MOS-FET RF power inverter because the output current and/or voltage waveform is other than sinusoidal. In order to satisfy the requirement, the online measurement of the output power of this type of RF power inverter by the use of the PC-98 personal computer has been presented. The current and voltage waveforms are sensed by the digital oscilloscope probes so as to obtain the instantaeous power and they are entered into the PC98 personal computer so as to average the instantaneous powers. The RF power of up to 1 kw at 1 MHz measured for the power inverter at the output transformer. This method was confirmed to be applied to evaluate the load resistance change with temperature.

• 대한기계학회논문집A
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• 제24권4호
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• pp.1039-1046
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• 2000

This paper introduces the control and measurement of a double parallel robot manipulator applied for unknown geometric surface grinding. A measurement system is developed to recognize a grinding path by a vision camera and to observe a grinding load by a current sensor. With the measured fusion information, an intelligent controller identifies the unknown geometric surface and moves the robot along the grinding path with a constant grinding load.

• Ocean and Polar Research
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• 제33권2호
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• pp.171-183
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• 2011

Despite technological developments and application advances of Acoustic Doppler Current Profilers (ADCPs), no standard procedure has been adopted or accepted for calibration of ADCPs. Limitations of existing facilities for calibrating ADCPs, the complexity of ADCP instruments, and rapid changes in ADCP technology are some of the reasons why a standard procedure has not been adopted. However, there is increasing realization of the need for effective Quality Assurance (QA) and as part of that the importance of standardized calibration. In this study, the significance of calibration and QA plans for ADCPs is discussed and the calibration facilities for ADCPs at home and abroad are reported. Furthermore, the method for calibrating ADCPs using a towed car and its limitations are discussed. This study contributes to discussions surrounding the establishment of standard procedures for calibrating ADCPs and QA plans, and the construction of calibration facilities in the future.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1194-1197
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• 2004

High temporal-resolution and accurate measurement of skin impedance locus provides useful data for the identification of the physiological/psychological changes and also the identification of acupuncture point. An impedance spectroscopy method using digitally constructed current waveform consisting of many frequency components (multiples of 1Hz) was reported3. The time resolution of the method depends on the lowest frequency used in the waveform construction, and therefore, the measurement would be faster if the lowest frequency is the higher. However, it was not clear that how many and how low frequencies must be used for the estimation of the skin impedance parameters from which the impedance locus can be drawn. This study shows the relationship between the estimation error of the impedance parameters and the frequency coverage of the spectroscopy. The results of this study are expected to serve as the reference of the frequency selection in the impedance spectroscopy.

• 한국소음진동공학회논문집
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• 제17권4호
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• pp.333-341
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• 2007

Waveform design method for inkjet printing has been proposed tv pressure wave measurement. The pressure wane inside the inkjet dispenser can be effectively measured by current measurement due to self-sensing capability of PZT. The pressure wave measured from current was verified by commercially availablelaser vibrometer. In order to obtain high speed inkjet droplets, two pulse waveform was designed such that the pressure wane after droplet formation can be minimized.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.366-372
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• 2007

Self-sensing measurement of piezo inkjet and its application are discussed. The pressure wave inside the inkjet dispenser was measured by current measurement due to self-sensing capability of PZT. The pressure wave measured from current was verified by commercially available laser vibrometer. Here, two applications using self-sensing signal were discussed: waveform design for high speed jetting and condition monitoring. For waveform design, two pulse waveform was designed based on self-sensing signal such that the pressure wave after droplet formation can be minimized. For condition monitoring, self-sensing signal was shown to be effective in detecting air bubble trapped in inkjet printhead.