• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1346-1354
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• 2018

Quality of the power system depends upon the reliability of its components such as transformer, transmission lines, insulators, circuit breakers and isolators. The transient voltage due to internal or external reasons may affect the insulation level of the components. The insulation level of these components must be tested against these conditions. Different studies, testing of different electrical components against high voltage impulses and different industrial applications rely on the international manufactures for pulsed power generation and testing, that is quite expensive and large in size. In this paper a model of impulse voltage generator with capacitive load of pin type insulator is studied by simulation method and by an experimental setup. A ten stage high voltage impulse generator (HVIG) is designed and implemented for different applications. In this proposed model, the cost has been reduced by using small and cheap capacitors as an alternative for large and expensive ones while achieving the same effectiveness. Effect of the distributed capacitance in each stage is analyzed to prove the effectiveness of the model. Different values of front and tail resistances have been used to get IEC standard waveforms. Results reveal the effectiveness at reduced cost of the proposed model.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.2
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• pp.63-68
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• 2005

Total 12 units of high power klystron-modulator systems as microwave source are under operation for 2.5 GeV electron linear accelerator in Pohang Light Source (PLS) linac. The klystron-modulator system has an important role for the stable operation to improve an availability statistics of overall system performance of klystron-modulator system. RF power and beam power of klystron are precisely measured for the effective control of electron beam. A precise measurement and measurement equipment with good response characteristics are demanded for this. Input power of klystron is calculated from the applied voltage and the current on its cathode. Tiny measurement error severely effects RF output power value of klystron. Therefore, special care is needed to measure precise beam voltage. Capacitive voltage divider (CVD), which divides input voltage as capacitance ratio, is intended for the measurement of a beam voltage of 400 kV generated from the klystron-modulator system. Main parameter to determine standard capacitance in the high arm of CVD is dielectric constant of insulation oil. Therefore CVD should be designed to have a minimum capacitance variation due to voltage, frequency and temperature in the measurement range. This paper will be present and discuss the design concept and analysis of capacitive voltage divider for a pulsed high-voltage measurement, and the empirical relations between capacitance effects and oil temperature variation.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.677-678
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• 2008

In this study, the method for the measurement of harmonics at nonsinusodial signal, which utilizes two synchronized high precision digital multimeters has been developed. The harmonics of voltage and current waveforms were computed from the acquired digitize samples through the DMMs and using developed software which based on FFT algorithm. The system can be used as a reference system to calibrate harmonic analyzers.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2030-2031
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• 2008

We have developed the calibration technique of the VT comparator using nonreactive standard resistors and a standard capacitor, which evaluates both accuracy and linearity of the VT comparator by comparing experimental values with theoretical values. The specification for phase displacement of VT comparator have been revaluated.

• Journal of radiological science and technology
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• v.37 no.1
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• pp.1-6
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• 2014

Breast shooting performance management and quality control of the generator is applied to the amount of current IEC(International Electrotechnical Commission) 60601-2-45 tube voltage and tube current are based on standards that were proposed in the analysis of the test results were as follows. Tube voltage according to the value of the standard deviation by year of manufacture from 2001 to 2010 as a 42-3.15 showed the most significant, according to the year of manufacture by tube amperage value of the standard deviation to 6.38 in the pre-2000 showed the most significant, manufactured after 2011 the standard deviation of the devices, the PAE(Percent Average Error) was relatively low. This latest generation device was manufactured in the breast of the tube voltage and tube diagnosed shooting the correct amount of current to maintain the performance that can be seen. The results of this study as the basis for radiography diagnosed breast caused by using the device's performance and maintain quality control, so the current Food and Drug Administration "about the safety of diagnostic radiation generator rule" specified in the test cycle during three years of self-inspection radiation on a radiation generating device ensure safety and performance of the device using a coherent X-ray(constancy) by two ultimately able to keep the radiation dose to the public to reduce the expected effect is expected.

• Journal of Sensor Science and Technology
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• v.3 no.3
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• pp.16-21
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• 1994

A 3-terminal pin-type photosensor with gate contrail is fabricated using standard silicon CMOS IC process. The photosensor of a $100{\mu}m{\times}120{\mu}m$ size has dark current less than 1nA and its breakdown voltage is -14V with a depletion capacitance 0.75 pF at -5V reverse bias. Responsivity at 0V gate voltage is 0.25A/W at $0.633{\mu}m$ wavelength, 0.19A/W at $0.805{\mu}m$. Responsivity increases with increasing gate voltage. The integrated circuit of photosensor and CMOS inverter shows $22K{\Omega}$ transimpedance and photocurrent of $90{\mu}A$ switchs the output state of digital inverter without additional amplifier.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.886-892
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• 2000

In this paper, surface transfer impedance measurement of RF cables according to IEC(International Electrotechnical Commission) Standard 96-1 is described and surface transfer impedance of a commercial RF cable is obtained from the measured voltage and scattering parameter with a triaxial fixture fabricated in the operating frequency range from 1 MHz to 30 MHz.

• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.15-21
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• 2014

An electrostatic discharge (ESD) protection device, so called, N-type embedded silicon controlled rectifier (NESCR), was analyzed for high voltage operating I/O applications. A conventional NESCR standard device shows typical SCR-like characteristics with extremely low snapback holding voltage, which may cause latch-up problem during normal operation. However, our modified NESCR_CPS_PPW device with proper junction/channel engineering such as counter pocket source (CPS) and partial P-well structure demonstrates highly latch-up immune current-voltage characteristics with high snapback holding voltage and on-resistance.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.279-284
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• 2005

We investigated the impedance matching characteristics of UHF-band RFID tag antenna and tag chip for increased reading range. A voltage multiplier designed using 0.4 $\mu$m zero-$V_T$ MOSFET showed that DC output voltage of about 2 V can be obtained using standard CMOS process. The input impedance of the voltage multiplier was examined to achieve impedance matching to the RFID tag antenna using analytical and numerical approaches. The input impedance of the voltage multiplier could be varied in a wide range by selecting the size of MOSFET and the number of multiplying stages, and thus can be impedance matched to a tag antenna in presence of other tag circuit blocks. A meander line inductively-coupled RFID tag antenna operating at UHF band also shows the feasibility of impedance matching to tile RFID tag chip.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.7
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• pp.1079-1083
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• 2002

We made ESD tester to measure ESD threshold voltage of semiconductor devices. The HBM ESD test is the most popular method to measure the ESD threshold voltage of MMSIC. We use flyback method which is one of the DC-DC converter to get high ESD voltage. With flvback method, we can isolate the 1ow voltage part from the high voltage part of HBM ESD tester. We use an air gap of the relay which is used for switch to satisfy the rise time of ESD standard(MIL-STD). As a result, with the flyback method and the air gap of relay, we can make ESD tester whose parasitic components are minimized.