• 전기학회논문지
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• 제60권4호
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• pp.899-904
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• 2011

Inspections and diagnoses of corona discharge are important in order to prevent electrical faults of external insulation in power systems. This paper studies a measurement of ultra-violet rays(UV) strength of corona discharges on insulators using a UV sensor with an optic lens. The data has been compared with the images of a UV camera. The UV sensor estimated that DC voltage needed to be set at 700V for accurate data analysis of the properties of UV detected during corona discharge. UV was generated at 60kV when the corona discharge occurred. UV strength and images of UV increased at a high voltage. The image area of the UV using a UV camera and the detection of UV using a UV sensor have shown, that the polymer insulator mounted on a live part must be checked when the applied voltage on the good polymer insulator is greater than 37.5% of its breakdown voltage.

• 디지털산업정보학회논문지
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• 제10권2호
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• pp.37-45
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• 2014

This paper is a study of the water sensor using a coaxial cavity resonator. This water sensor uses the resonant frequency variation of the coaxial cavity resonator when there is a water drop of the used coaxial cavity resonator. And we made resonant frequencies by controlling the input voltage of the oscillator which will be mainly resonated in the coaxial cavity resonator. First, we made the coaxial cavity resonator by simulating the resonator structure with the proposed size and we expect the resonant frequency from the simulation and then we decide the VCO from the result. Second, we made the water drop detecting sensor circuit and measured the water sensor. We decided the size of the resonator as inner conductor 5mm, outer conductor 14mm, the height of resonator 9.5mm, and the height of the glass 6mm from the simulated result. The simulated resonant frequencies are 3.09GHz and we made the VCO frequency ranges from 2.56GHz to 3.2GHz. The measured resonant frequency is 2.97GHz and the return loss is under -8. 4 dB at the center frequency. When the water is dropped on the glass of the resonator, the voltage has changed from 690mV to 145mV. It shows the proposed water sensor can detect the water by the resonant frequency variation of the resonator.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권1호
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• pp.29-34
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• 2017

A CMOS-based temperature sensor is proposed for low-voltage and low-power on-chip thermal monitoring applications. The proposed temperature sensor converts a proportional to absolute temperature (PTAT) current to a PTAT frequency using an integrator and hysteresis comparator. In addition, it operates in the subthreshold region, allowing reduced power consumption. The proposed temperature sensor was fabricated in a standard 90 nm CMOS technology. Measurement results of the proposed temperature sensor show a temperature error of between -0.81 and $+0.94^{\circ}C$ in the temperature range of 0 to $70^{\circ}C$ after one-point calibration at $30^{\circ}C$, with a temperature coefficient of $218Hz/^{\circ}C$. Moreover, the measured energy of the proposed temperature sensor is 36 pJ per conversion, the lowest compared to prior works.

• 전기학회논문지P
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• 제55권1호
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• pp.31-34
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• 2006

A infrared rays sensor or ultrasonic sensor can detect the object at the narrow area, however a pressure sensor can detect man and animal at the wide area. It is necessary to manufacture the sensor by using Pb-free ceramics in the respect of environmental protection. Piezoelectric properties of ceramics added 0.2wt% $La_2O_3\;into\;0.96Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}+0.04SrTiO_3$ were 0.4 of kp, $31{\times}$10^{-3}Vm/N\;of\;g_{33}$. The output voltage of the pressure sensor is 0.48 V at 20 in$H_2O$. The output voltage of the pressure sensor with driving circuit is 9.8 V, 37 ms width.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1038-1041
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• 2003

The magnetic suspension system is used in many areas, because it has great advantages. such as no friction, no noise, no lubrication and so on, but it is a unstable system in natural. It must have a feedback control with the position is measured for a stable levitation. There are an eddy-current sensor, a capacitive sensor, an inductive sensor, and an optical sensor with a laser as the sensor which measures displacements without contact. Among them, an inductive sensor is made with lower price than others. And it has a good linearity. In this paper, a magnetic circuit leads a linear equation between an input as a displacement and an output as a voltage. Experiments establish that voltage change according to displacement is linear. This paper presents the preliminary study of an inductive position sensing for self-sensing magnetic suspension system.

• 한국전기전자재료학회논문지
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• 제27권4호
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• pp.257-261
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• 2014

Carbon nanotubes (CNT) has the excellent physical characteristics in the sensor, medicine, manufacturing and energy fields, and it has been studied in those fields for the several years. We fabricated the NOx gas sensors of MOS-FET type using the MWCNT. The fabricated sensor was used to detect the NOx gas for the variation of $V_{gs}$ (gate-source voltage) with the ambient temperature. The gas sensor absorbed the NOx gas molecules showed the decrease of resistance, and the sensitivity of sensor was reduced by the NOx gas molecules accumulated on the MWCNT surface. Furthermore, when the voltage ($V_{gs}$) was applied to the gas sensor, the term of the decrease in resistance was increased. On the other hand, the sensor sensitivity for the injection of NOx gas was the highest value at the ambient temperature of $40^{\circ}C$. We also obtained the adsorption energy ($40^{\circ}C$) using the Arrhenius plots by the reduction of resistance due to the $V_{gs}$ voltage variations. As a result, we obtained that the adsorption energy also was increased with the increasement of the applied $V_{gs}$ voltages.

• Design & Manufacturing
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• 제16권4호
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• pp.52-59
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• 2022

Currently, Korea is an aging society and is expected to become a super-aged society in about four years. X-ray devices are widely used for early diagnosis in hospitals, and many X-ray technologies are being developed. The development of X-ray device technology is important, but it is also important to increase the reliability of the device through accurate data management. Sensor nodes such as temperature, voltage, and current of the diagnosis device may malfunction or transmit inaccurate data due to various causes such as failure or power outage. Therefore, in this study, the temperature, tube voltage, and tube current data related to each sensor and detection circuit of the diagnostic X-ray imaging device were measured and analyzed. Based on QC data, device failure prediction and diagnosis algorithms were designed and performed. The fault diagnosis algorithm can configure a simulator capable of setting user parameter values, displaying sensor output graphs, and displaying signs of sensor abnormalities, and can check the detection results when each sensor is operating normally and when the sensor is abnormal. It is judged that efficient device management and diagnosis is possible because it monitors abnormal data values (temperature, voltage, current) in real time and automatically diagnoses failures by feeding back the abnormal values detected at each stage. Although this algorithm cannot predict all failures related to temperature, voltage, and current of diagnostic X-ray imaging devices, it can detect temperature rise, bouncing values, device physical limits, input/output values, and radiation-related anomalies. exposure. If a value exceeding the maximum variation value of each data occurs, it is judged that it will be possible to check and respond in preparation for device failure. If a device's sensor fails, unexpected accidents may occur, increasing costs and risks, and regular maintenance cannot cope with all errors or failures. Therefore, since real-time maintenance through continuous data monitoring is possible, reliability improvement, maintenance cost reduction, and efficient management of equipment are expected to be possible.

• 센서학회지
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• 제5권6호
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• pp.25-34
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• 1996

본 논문에서는 압저항형 압력센서를 위한 신호처리회로를 설계하였다. 신호처리회로는 압저항형 압력센서를 구동하기 위한 기준전압 회로와 미소한 센서 신호의 증폭을 위한 인스트루먼트 증폭기로 구성이 되어있다. 신호처리회로는 단일 폴리 이중 메탈(single poly double metal) $1.5\;{\mu}m$ BiCMOS 공정 파라미터를 이용하여 HSPICE로 시뮬레이션 하였다. 시뮬레이션 결과, 밴드갭 기준전압회로의 온도 계수는 $0\;{\sim}\;70^{\circ}C$의 범위에서 $21\;ppm/^{\circ}C$였고 PSRR은 80 dB였다. BiCMOS 증폭기의 이득, 옵셋, CMRR, CMR, PSRR, 특성은 CMOS나 바이폴라보다 우수하였고 전력소비 및 잡음전압 특성은 CMOS가 우수하였다. 설계한 신호처리 회로는 옵셋이 적고 입력 임피던스가 높으며 CMRR 특성이 우수하기 때문에 센서 및 계측용 신호처리회로로서 사용하기에 적합하다.

• 센서학회지
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• 제25권2호
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• pp.124-130
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• 2016

NDIR $CO_2$ gas sensor was built with ASIC implemented thermopile sensor which included temperature sensor and unique elliptical waveguide structures in this paper. The temperature dependency of dual infrared sensor module ($CO_2$ and reference IR sensors) has been characterized and its output voltage characteristics according to the temperature and gas concentration were proposed for the first time. NDIR $CO_2$ gas and reference IR sensors showed linear output voltages according to the variation of ambient temperatures from 243 K to 333 K and their slopes were 14.2 mV/K and 8.8 mV/K, respectively. The output voltages of temperature sensor also presented a linear dependency according to the ambient temperature and could be described with V(T)=-3.191+0.0148T(V). The output voltage ratio between $CO_2$ and reference IR sensors revealed irrelevant to the changes of ambient temperatures and gave a constant value around 1.6255 with standard deviation 0.008 at 0 ppm. The output voltage of $CO_2$ gas sensor at zero ppm $CO_2$ gas consisted of two components; one is caused by the HPB (half pass-band) of IR filter and the other is attributed to the part of $CO_2$ absorption wavelength. The characteristics of output voltages of $CO_2$ gas sensor could be accurately modeled with three parameters which are dependent upon the ambient temperatures and represented small average error less than 1.5% with 5% standard deviation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1427_1428
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• 2009

In this paper, we designed and fabricated the ubiquitous thermal sensor unit for high voltage facilities. This sensor unit generates electric power from a current transformer which was mounted in the high voltage wires and transmitted thermal data by using a Zigbee module. We simulated the high voltage facilities that temperature was going up to $80^{\circ}C$ gradually. From the experimental results, it was confirmed that sensibility of the ubiquitous thermal sensor unit is in ranges from $-0.7^{\circ}C$ to $0.3^{\circ}C$.