This article presents the microelectronic transducer of gas concentration. The transducer have been used in the absorption spectroscopy technique equipment for measuring concentration of combustible gases. The transducer contains photoresistor and semiconductor structure and provides converting of informative optical signal into the output frequency one. The proposed transducer is low-cost in both material and fabrication and can be used for measuring weak changes of gases. The mathematical model of the microelectronic transducer which describes the transfer function and sensitivity has been calculated. The developed transducer shows a high sensitivity up to 150 Hz/ppm
Słowa kluczowe: frequency transducers, negative resistance, gas concentration
Zaprezentowano mikroelektroniczny przetwornik koncentracji gazu (spalin) wykorzystujący spektroskopię absorpcji. W układzie przetwarzającym sygnał optyczny na częstotliwość wykorzystano fotorezystor.
Keywords: przetwornik koncentracji gazu, fotorezystor, MOSFET
Transducers of gas concentration are widely used in the chemical and oil and gas industry for measuring of noxious gases concentration in the production and in the systems intended for environmental monitoring. The accuracy of the determination with control over time of the gas composition in the production and technological processes provides the appropriate quality of the executed work as well as ensures safety of working environment. The optical methods are considered as the most universal and simple methods for determination of gas concentration. The most perspective optical method is the absorption spectroscopy which has a low threshold of sensitivity (<1 μg/m3) and high selectivity. In the case of small concentrations of controlled substances, the sensitivity can be enhanced by increase in the thickness of the layer in which absorption occurs. Moreover, the advantages of this method include the multipurpose usefulness, high speed of measurements and simplicity of the implementation in the automated systems. The absorption spectroscopy method, based on the phenomenon of selective absorption of radiation by gases, is the basis of many devices. The selective absorption is explained by the fact that the radiation frequency is resonant for molecules of a certain gas. When light is absorbed, the atoms and molecules of substances pass into a new excited state. The basic gases which concentrations can be determined by the optical method with the optimal wavelengths to occur of absorption in the different areas of the infrared range are presented in . Nowadays, there is a plenty of gas analyzers for a wide variety of gases. The parameters of gas analyzers with operation based on selective absorption of infrared (IR) band radiation by gases from a hydrocarbon group with a wavelength of 2 ÷ 5 μm are given in the papers [2-6]. The parameters of gas analyzers operating on the base of selective absorption of infrared [...]
 Werle P. , Slemr F., Maurer K., Kormann R., Muecke R. , Jaenker B. Near- and mid-infrared laseroptical sensors for gas analysis, Optics and Lasers in Engineering 37,(2002), 101-114  Shimose Y. , Okamoto T . , Maruyama A . , Aizawa M., Nagai H. Remote sensing of methane gas by differential absorption measurement using a wavelength tunable DFB LD, IEEE Photonics Technology Letters, 3 (1991), n. 1, 86-87  Zavadovsky A., Plyusnin I., Sysoev S. Compact locator of methane leaks, Sensors and systems, (2007), n. 4, 28-30  Vasiliev A. , Shenanin V. , Charty P. Infrared detector for measuring concentrations of toxic gas molecules in the air stream, Patent RU, no. 2484450, (2013)  Michael D. Jack, Robert D. Stephens e t a l . , Optical sensing apparatus for remotely measuring exhaust gas composition of moving motor vehicles, Patenst US, n. 5591975, (1997)  Baranov A.M. , Sleptsov V.V. et al . Multi-wavelength trace gas analyzer, Patent RU, № 174760, G01N 21/01 (2016)  O’Keefe A., Deacon D.A.G. Cavity ring-down optical spectrometer for absorption measurements using pulsed laser sources, Review of Scientific Instruments, 59 (1988).  Osadchuk V.S. , Osadchuk A.V. Radiomeasuring Microelectronic Transducers of Physical Quantities, IEEE, Proceedings of the International Siberian Conference on Control and Communications (SIBCON), 21-23 May, (2015)  Kwang-Jow Gan, Kuan-Yu Chun, Wen-Kuan Yeh, Muecke R. , Jaenker B. Design of Dynamic Frequency Divider using Negative Differential Resistance Circuit, International Journal on Recent and Innovation Trends in Computing and Communication 3, (2015), n. 8, 5224-5228  Osadchuk O.V., Osadchuk V.S., Osadchuk I.O., Kolimoldayev M., Komada P., Mussabekov K. Design of Dynamic Frequency Optical transducers with frequency output, Proc. SPIE 10445, Photonics Applications in Astronomy, Communications, Industry, and High Energy Physics Experiments 104451X, (2017)  Osadchuk V.S., Osadchuk A.V., Yushchenko Y.A. Radiomeasuring thermal flowmeter of gas on the basis of transistor structure with negative resistance, Elektronika ir Elektrotechnika. Kaunas: Technologija 84, (2008), n. 8, 89-93  Osadchuk V.S., Osadchuk A.V., Osadchuk I .O, Kisała P., Zyska T., Annabaev A., Mussabekov K. Radiomeasuring pressure transducer with sensitive MEMS capacitor, Przegląd Elektrotechniczny, 93, (2017), 113-116  Alexeev V.А., Yatsenko V.А . The experience of creating portable multicomponent gas analyzers using the optical absorption method, Radioengineering, (2006), n. 146, 192-197  Osadchuk V.S., Osadchuk O.V., Seletska O.O. Radiomeasuring optical converters for microelectronic technology: monograph, Universum, Vinnytsia, Ukraine, (2013)  Kayat s kas A.A. Basics of electronics, Moskow: Executive. wk., (1988)