• Title/Summary/Keyword: Temperature Sensitivity

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Temperature Compensated Hall-Effect Power IC for Brushless Motor

  • Lee, Cheol-Woo;Jang, Kyung-Hee
    • Proceedings of the IEEK Conference
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    • 2002.07a
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    • pp.74-77
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    • 2002
  • In this paper we present a novel temperature compensated Hall effect power IC for accurate operation of wide temperature and high current drive of the motor coil. In order to compensate the temperature dependence of Hall sensitivity with negative temperature coefficient(TC), the differential amplifier has the gain consisted of epi-layer resistor with positive TC. The material of Hall device and epi-resistor is epi-layer with the same mobility. The variation of Hall sensitivity is -38% at 150$^{\circ}C$ and 88% at - 40$^{\circ}C$. But the operating point(B$\sub$op/) and release point(B$\sub$RP/) of the Hall power IC are within ${\pm}$25%. The experimental results show very stable and accurate performance over wide temperature range of -40$^{\circ}C$ to 125$^{\circ}C$.

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Fabrication of polycrystalline 3C-SiC micro pressure sensors for hightemperature applications (초고온용 다결정 3C-SiC 마이크로 압력센서의 제작)

  • Chung, Gwiy-Sang
    • Journal of Sensor Science and Technology
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    • v.19 no.1
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    • pp.31-35
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    • 2010
  • High temperature micro pressure sensors were fabricated by using polycrystalline 3C-SiC piezoresistors grown on oxidized SOI substrates by APCVD. These have been made by bulk micromachining under $1{\times}1mm^2$ diaphragm and Si membrane thickness of $20{\mu}m$. The pressure sensitivity of implemented pressure sensors was 0.1 mV/$V{\cdot}bar$. The nonlinearity and the hysteresis of sensors were ${\pm}0.44%{\cdot}FS$ and $0.61%{\cdot}FS$. In the temperature range of $25^{\circ}C{\sim}400^{\circ}C$ with 5 bar FS, TCS (temperature coefficient of sensitivity), TCR (temperature coefficient of resistance), and TCGF (temperature coefficient of gauge factor) of the sensor were -1867 ppm/$^{\circ}C$, -792 ppm/$^{\circ}C$, and -1042 ppm/$^{\circ}C$, respectively.

Development of the High Temperature Silicon Pressure Sensor (고온용 실리콘 압력센서 개발)

  • Kim, Mi-Mook;Nam, Tae-Chul;Lee, Young-Tae
    • Journal of Sensor Science and Technology
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    • v.13 no.3
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    • pp.175-181
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    • 2004
  • A pressure sensor for high temperature was fabricated by using a SDB(Silicon-Direct-Bonding) wafer with a Si/$SiO_{2}$/ Si structure. High pressure sensitivity was shown from the sensor using a single crystal silicon of the first layer as a piezoresistive layer. It also was made feasible to use under the high temperature as of over $120^{\circ}C$, which is generally known as the critical temperature for the general silicon sensor, by isolating the piezoresistive layer dielectrically and thermally from the silicon substrate with a silicon dioxide layer of the second layer. The pressure sensor fabricated in this research showed very high sensitivity as of $183.6{\mu}V/V{\cdot}kPa$, and its characteristics also showed an excellent linearity with low hysteresis. This sensor was usable up to the high temperature range of $300^{\circ}C$.

New Compensation Method for Temperature Sensitivity of Fiber Brags Grating Using Bi-metal

  • Chung, Young-Joo;Song, Jong-Seob;Han, Won-Taek;Paek, Un-Chul
    • Journal of the Optical Society of Korea
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    • v.7 no.2
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    • pp.84-88
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    • 2003
  • A new method for temperature compensation of fiber Bragg grating (FBG) using hi-metal is proposed and experimentally demonstrated. Bi-metal bends toward the metal of low temperature expansion coefficient as the temperature increases, and this property is utilized to cancel the thermo-optic effect of the fiber. The optimum thickness of the high coefficient metal was empirically found by the trial-and-error method. The temperature sensitivities were 8.1 pm/$^{\circ}C$ and -0.018 pm/$^{\circ}C$ for the uncompensated and compensated FBGs, respectively, which indicates a reduction to a mere 0.22 % of the original sensitivity. No appreciable change in the spectral shape was observed. The packaging technique described in this paper is simple and compact, and it can be used for FBGs in WDM and DWDM communication systems that have stringent requirements on the temperature stability of the components.

Capacitive force sensor

  • Miyazawa, S.;Usui, Y.;Suzuki, M.;Baba, S.
    • 제어로봇시스템학회:학술대회논문집
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    • 1994.10a
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    • pp.611-615
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    • 1994
  • In this paper, the sensitivity, linearity and temperature drift characteristics of various capacitive force sensors are evaluated and compared using new experimental methods. In particular, two designs were employed to reduce temperature drift. Both types of sensor use high-sensitivity Al coated PET film, and their externals are miniaturized. The first has a layered design consisting of two dielectric substances with different temperature characteristics. The prototype of this design had a temperature drift of only 0.1% of the sensor's capacity in the 20-80.deg. C range. The second type uses both a dummy sensor ind an active sensor with the same characteristics. The temperature drift of the prototype was one-fifth the temperature drift of a single sensor.

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Sensibility Evaluation on the Correlated Color Temperature in White LED Lighting (백색 LED 조명의 색온도에 관한 감성평가)

  • Jee, Soon-Duk;Lee, Sang-Hyuk;Choi, Kyoung-Jae;Park, Joung-Kyu;Kim, Chang-Hae
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.4
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    • pp.1-12
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    • 2008
  • The aim of this study is to investigate the sensitivity evaluation of human beings in reacting to the correlated color temperature of the optical properties of white LED lighting. For the sake of this study, white light-emitting diode modules have been fabricated their correlated color temperature have been measured, test cabinets for the sensitivity evaluation have been constructed with the white LED modules, and their sensitivity reactions on the test cabinets have been evaluated and analyzed. The sensitivity reaction has been evaluated by the semantic differential method with 15 selected questions, and the reliability and the content validity of their lighting have been analyzed to 3 factors which foe the activity as the first factor, the stability as the second one, the potency as the third one, respectively. For the data analysis on the sensitivity reaction, the dependent variable is the score of the sensitivity evaluation and the independent one is the correlated color temperature of the test module. The results of this study is as follows: In the case of the sensitive evaluation on the activity and the potency in the white LED lighting compared with the fluorescent lamp, the subjects have made higher mark on $MA_3$ with 8,300[K], and in the factor of the stability, they have made higher mark on $MA_1$ with 3,800[K].

Long-term monitoring of ground anchor tensile forces by FBG sensors embedded tendon

  • Sung, Hyun-Jong;Do, Tan Manh;Kim, Jae-Min;Kim, Young-Sang
    • Smart Structures and Systems
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    • v.19 no.3
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    • pp.269-277
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    • 2017
  • Recently, there has been significant interest in structural health monitoring for civil engineering applications. In this research, a specially designed tendon, proposed by embedding FBG sensors into the center king cable of a 7-wire strand tendon, was applied for long-term health monitoring of tensile forces on a ground anchor. To make temperature independent sensors, the effective temperature compensation of FBG sensors must be considered. The temperature sensitivity coefficient ${\beta}^{\prime}$ of the FBG sensors embedded tendon was successfully determined to be $2.0{\times}10^{-5}^{\circ}C^{-1}$ through calibrated tests in both a model rock body and a laboratory heat chamber. Furthermore, the obtained result for ${\beta}^{\prime}$ was formally verified through the ground temperature measurement test, expectedly. As a result, the ground temperature measured by a thermometer showed good agreement compared to that measured by the proposed FBG sensor, which was calibrated considering to the temperature sensitivity coefficient ${\beta}^{\prime}$. Finally, four prototype ground anchors including two tension ground anchors and two compression ground anchors made by replacing a tendon with the proposed smart tendon were installed into an actual slope at the Yeosu site. Tensile forces, after temperature compensation was taken into account using the verified temperature sensitivity coefficient ${\beta}^{\prime}$ and ground temperature obtained from the Korean Meteorological Administration (KMA) have been monitored for over one year, and the results were very consistent to those measured from the load cell, interestingly.

A Study on the Parameters of WASP5 Model in Daechung Reservoir (대청호에서 WASP5 모델 매개변수에 관한 연구)

  • Han, Woon Woo;Kim, Kyu-Hyung;Ahn, Tae-Bong
    • Journal of the Korean GEO-environmental Society
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    • v.4 no.3
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    • pp.69-77
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    • 2003
  • This study was carried out to evaluate the WASP5 model parameters and to analyze the sensitivity of parameters in Daechung Reservoir. The values predicted by the model and tendency were very similar to the observed data at Daejeon intake, so it is possible to predict water quality of the Daejeon intake region in the future. Results from the sensitivity analysis showed that Chlorophyll-a was sensitive to variations in saturated growth rate of phytoplankton, endogenous respiration rate of phytoplankton, extinction coefficient and temperature. T-N was sensitive to mineralization rate of dissolved organic nitrogen and temperature. T-P was affected by T-P load, temperature, extinction coefficient, mineralization rate of dissolved organic phosphorus and saturated growth rate of phytoplankton. BOD was influenced by deoxygenation rate and temperature, and DO was influenced by temperature. Adequate input data was applied and assessed through the model sensitivity analysis. So it is possible to distinguish the input data which need careful attention when it has application to model.

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Low temperature-operating NiO-CoO butane gas sensors

  • Jung, Dong-Ho;Choi, Soon-Don;Min, Bong-Ki
    • Journal of Sensor Science and Technology
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    • v.17 no.4
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    • pp.303-307
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    • 2008
  • $NiO,\;Cu_2O,\;Mn_2O_3$ and $Cr_2O_3$ as p-type semiconductors were added in CoO with 15 wt.% ethylene glycol binder and measured the butane gas sensing characteristics. The highest sensitivity is obtained for the NiO-CoO sensors. CoO-20 at.% NiO sensor with 15 wt.% ethylene glycol binder sintered at $1100^{\circ}C$ for 24 h exhibits high sensitivity of 90 % to 5000 ppm butane gas at the sensor temperature of $250^{\circ}C$, compared to low sensitivities at the low operating temperature for commercial sensors. Response and recovery times are, respectively, within few seconds and 1min in the static flow system, indicating rapid adsorption and desorption of butane gas on sensor surface even at this low temperature.

Characteristics of high-temperature single-crystalline 3C-SiC piezoresistive pressure sensors (고온 단결정 3C-SiC 압저항 압력센서 특성)

  • Thach, Phan Duy;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.274-274
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    • 2008
  • This paper describes on the fabrication and characteristics of a 3C-SiC (Silicon Carbide) micro pressure sensor for harsh environment applications. The implemented micro pressure sensor used 3C-SiC thin-films heteroepitaxially grown on SOI (Si-on-insulator) structures. This sensor takes advantages of the good mechanical properties of Si as diaphragms fabricated by D-RIE technology and temperature properties of 3C-SiC piezoresistors. The fabricated pressure sensors were tasted at temperature up to $250^{\circ}C$ and indicated a sensitivity of 0.46 mV/V*bar at room temperature and 0.28 mV/V*bar at $250^{\circ}C$. The fabricated 3C-SiC/SOI pressure sensor presents a high-sensitivity and excellent temperature stability.

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