• Title/Summary/Keyword: Sensor resistance

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A Design of Capacitive Sensing Touch Sensor Using RC Delay with Calibration (캘리브래이션 기능이 있는 RC지연 정전용량 방식 터치센서 설계)

  • Seong, Kwang-Su;Lee, Mu-Jin
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.8
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    • pp.80-85
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    • 2009
  • In this paper, we propose a full digital capacitive sensing touch key reducing the effects due to the variations of resistance and clock frequency. The proposed circuit consists of two capacitive loads to measure and a resistor between the capacitive loads. The method measures the delays of the resistor and two capacitive loads, respectively. The ratio of the two delays is represented as the ratio of the two capacitive loads and is irrelative to the resistance and the clock frequency if quantization error is disregarded. Experimental results show the proposed scheme efficiently reduces the effects due to the variations of clock frequency and resistance. Further more the method has 1.04[pF] resolution and can be used as a touch key.

Fast Responding Gas Sensors Using Sb-Doped SnO2 Nanowire Networks (Sb-첨가 SnO2 나노선 네트워크를 이용한 고속응답 가스센서)

  • Kwak, Chang-Hoon;Woo, Hyung-Sik;Lee, Jong-Heun
    • Journal of Sensor Science and Technology
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    • v.22 no.4
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    • pp.302-307
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    • 2013
  • The Sb-doped $SnO_2$ nanowire network sensors were prepared by thermal evaporation of the mixtures between tin and antimony powders. Pure $SnO_2$ nanowire networks showed high sensor resistance in air ($99M{\Omega}$), similar gas responses to 4 diffferent gases (5 ppm $C_2H_5OH$, CO, $H_2$, and trimethylamine), and very sluggish recovery speed (90% recovery time > 800 s). In contrast, 2 wt% Sb-doped $SnO_2$ showed the selective detection toward $C_2H_5OH$ and trimethylamine, relatively low resistance ($176k{\Omega}$) for facile measurement, and ultrafast recovery speed (90% recovery times: 6 - 18 s). The change of gas sensing charactersitics by Sb doping was discussed in relation to gas sensing mechanism.

Bistable Multivibrator Using Second Generation Current Conveyor and Its Application to Resistive Bridge Sensor (2세대 전류 컨베이어를 이용한 쌍안정 멀티바이브레이터 설계 및 저항형 브리지 센서에의 응용)

  • Chung, Won-Sup;Park, Jun-Min
    • Journal of IKEEE
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    • v.23 no.2
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    • pp.636-641
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    • 2019
  • A simple resistance deviation-to-time period converter is proposed for interfacing resistive half-bridge sensors. It consists of two 2nd generation current conveyors(CCIIs). The proposed converter has simpler circuit configuration than the conventional converters using operational amplifiers or operational transconductance amplifiers(OTAs). The proposed converter was simulated using CCII implemented with AD844 IC chips. The simulation results show that the converter has a conversion sensitivity of $0.01934ms/{\Omega}$ over a range of $100-500{\Omega}$ resistance deviations and a linearity error less than ${\pm}0.002%$.

Ethanol Gas Sensing Characteristics of Conducting Polymer Sensor Using Impedance (Impedance를 이용한 전도성고분자 센서의 에탄올 가스 감응특성)

  • Lee, Kyung-Mun;Yu, Joon-Boo;Jun, Hee-Kwon;Lee, Byung-Soo;Lee, Duk-Dong;Huh, Jeung-Soo
    • Korean Journal of Materials Research
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    • v.13 no.3
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    • pp.155-159
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    • 2003
  • The polypyrrole and polyaniline thin film sensors which were made by chemical polymerization were employed to detect ethanol gas. With a single sensor element we can obtain characteristic patterns of behaviour across a very wide frequency range when measuring either resistance or capacitance. Impedance spectroscopy was employed to study the gas sensing behavior of both capacitance and resistance based sensors with conducting polymer as the active sensing element.

A study on the characteristics of torque transducer (토오크 변환기의 특성에 대한 연구)

  • 최만용;임동규;한응교
    • Journal of the korean Society of Automotive Engineers
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    • v.4 no.3
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    • pp.48-55
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    • 1982
  • In the present the strain gauge type torque transducers consist of solid shaft as sensor, slip ring, brush and bridge circuit as detecting circuit. So in the case of measuring the low-capacity torque, the error caused by technical mistake in mounting stain gauge on the small sensor and especially by contact resistance between slip ring and brush takes place more than the large sensor. Therefore in this study constant voltage in order to have no effect of contact resistance is supplied to the hollow shaft and Schrobron Bridge Circuit. Through the experiment good results were obtained as follows; linearity, hysterisis and zero drift as static characteristics is within 1% F.S respectively. Also when loading, zero drift is about 2% F.S.

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Polymeric Humidity Sensor Using Polyelectrolyte Derived from Poly(amide-sulfone)s

  • Jeon, Young-Min;Gong, Myoung-Seon
    • Macromolecular Research
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    • v.17 no.4
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    • pp.227-231
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    • 2009
  • New polyelectrolytes derived from poly(amide-sulfone)s and 1,5-dibromopentane were simultaneously fabricated on the electrode by the crosslinking reaction. The substrate was pretreated with a bromoalkyl-containing, silane-coupling agent to anchor the humidity-sensitive membrane to the substrate through the covalent bond. When the resistance dependence on the relative humidity of the crosslinked poly(amide-sulfone)s was measured, the resistance varied by three orders of magnitude between 20%RH and 90%RH, which was the required RH range for a humidity sensor operating at ambient humidity. Their water durability, long-term stabilities under various environments, hysteresis and response and recovery times were measured and evaluated as a humidity-sensing membrane.

Study on The Corrosion Rate Monitoring of Steel in Concrete Using Electric resistance Sensor and Electrochemical Methods. (전기저항형 센서 및 전기화학적 방법을 이용한 철근콘크리트 구조물의 부식속도 측정 방법에 관한 연구)

  • 조용범;김용철;장상엽;고영태
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.1185-1192
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    • 2001
  • This paper reviews available techniques for monitoring corrosion of steel in concrete. The need for early detection and diagnosis of corrosion related deterioration in reinforced structures is widely acknowledged. This is particularly important in reinforced concrete structures on account of the economic and social significance of the problem. The current generally used on-site procedure for corrosion monitoring of reinforced structures employs a method of half-cell surface potential measurements. While the technique has provided a useful means of delineating areas of high or low corrosion risk, there are difficulties in its use and interpretation when assessing rates of deterioration. Electrochemical techniques are by far the most suitable for corrosion monitoring purpose and meet most of the requirements. The aim of this paper is to describe the electric resistance sensor(ER sensor) and electrochemical techniques employed to monitor and estimate corrosion rates of reinforcement. Early detection and diagnosis of corrosion hazards allows preventive measures to be taken, hence the typically expensive repair of severely deteriorated structures can be avoided.

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Fabrication of a Porous 3C-SiC Based Resistivity Hydrogen Sensor and Its Characteristics (다공성 3C-SiC 기반 저항식 수소센서의 제작과 그 특성)

  • Kim, Kang-San;Chung, Gwiy-Sang
    • Journal of Sensor Science and Technology
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    • v.20 no.3
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    • pp.168-171
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    • 2011
  • Porous 3C-SiC(pSiC) samples with different pore diameters were prepared from poly crystalline N-type 3C-SiC by electrochemical anodization. The pSiC surface was chemically modified by the sputtering of Pd and Pt nano-particles as a hydrogen catalyst. Changes in resistance were monitored with hydrogen concentrations in the range of 110 ppm - 410 ppm. The variations of the electrical resistance in the presence of hydrogen demonstrated that Pd and Pt-deposited pSiC samples have the ability to detect hydrogen at room temperature. Regardless of the catalyst, the 25 nm pore diameter samples showed good response and recovery properties. However, the 60 nm samples showed unstable and slow response. It was found that the pore size affects the catalyst reaction and consequently, results in changes of the sensitivity to hydrogen.

Humidity-Sensitive Properties of Self-Assembled Polyelectrolyte System

  • Lee Chil-Won;Kim Jong-Gyu;Gong Myoung-Seon
    • Macromolecular Research
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    • v.13 no.3
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    • pp.265-272
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    • 2005
  • Polyelectrolyte membranes for humidity-sensing were fabricated using a layer-by-layer adsorption process based on the spontaneous self-assembly of alternating layers of cationic and anionic polymers on a silanized ITO patterned glass substrate. The substrate is dipped successively into dilute solutions of a polyanion and a polycation. The homopolymers and copoymers of diallyldimethylammonium chloride (DDA), allylamine hydrochloride (AA), 2-[(methacryloyloxy)ethyl]trimethyl ammonium chloride (METAC) and vinylbenzyl tributyl phosphonium chloride(VTBPC) were used as the polycations. In this experiment, it was found that the resistance varied according to the chemical structure of the polycation. The resistance varied from $10^7$ to $10^5$ $\Omega$, as the humidity was increased from 60 (relative humidity) to $95\%$RH, which is the range of RH values required for a dew sensor operating at high humidity.

Detecting Characteristics of Catalytic Combustible Gas Sensor (접촉연소식 가스 센서의 검지특성)

  • 박찬원;원창섭;유영한;안형근;한득영
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.10
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    • pp.865-870
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    • 2000
  • In this paper, catalytic combustible gas sensor was fabricated and tested under flammable gases such as CH$_4$and $C_4$H$_{10}$by using Pt coil as a heater and/or temperature sensing element. Fine $Al_2$O$_3$powder was used for a bead and Pt, Pd noble metal powder for a catalyst. Resistance variation of Pt wire was traced by the changes of the gas concentrations in a chamber. Output voltage was then monitored to obtain the gas concentration from the resistance variation. In this experiment, MgO was used to protect cracks in the based and TiO$_2$to increase the sensitivity of the sensors. Water glass was also added to enhance the selectivity to the combustible gases.s.

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