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Gas sensors, cont.

Gas sensors, cont. Modulation of sensors working temperature. 400 ppm NO 2. 1000 CO + 400 NO 2. air. 1000 ppm CO. Pulse power supply of the sensors heater. Pellistor – type sensors. P ellistor wit a surface catalyst (diam. ca.1 mm). P ellistor fixed in an encapsulation.

maisie-barnett
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Gas sensors, cont.

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  1. Gas sensors, cont.

  2. Modulation of sensors working temperature 400 ppm NO2 1000 CO + 400 NO2 air 1000 ppm CO Pulse power supply of the sensors heater

  3. Pellistor – type sensors Pellistor wit a surface catalyst (diam. ca.1 mm) Pellistor fixed in an encapsulation

  4. Thermoconductometric sensors (catharometers) λG - heat conductivity of a gas M0– molecular weight d0- molecule diameter SEM picture of the flow channel with suspended Pt thermoresistor (magnification 212 x) μTAS with separation column and TCD detector for the analysis of chemical composition of a gas mixture

  5. Electrochemical sensors Lambda sensor characteristics at a working temp. ca. 600oC. Oxygen Lambda sensor of the finger type installed in an exhaust pipe. λ – air excess coefficient A – quantity of air F – quantity of a fuel

  6. Electrochemical amperometric sensors Oxygen sensor with a current limit caused by a slit. Thin film amperometric sensor with a current limit due to chemical reactions.

  7. Optical sensors Methane absorption in a main abs. band 3200 – 3400 nm; 1 – diode LED1, 2 - diode LED2, 3 - detector Two-diode system for absorption measurement in the NIR region

  8. Optical sensors Absorption spectrumA and fluorescence emission of DPB compoundin nitrogen atmosphereBand oxygen atmosphereC. Integrated fluorescence sensor coupled with a μTAS microchannel structure.

  9. Structues basd on the field effect MISFET type transistor as gas sensor. Gate metal – mostly Pd Change of the threshold voltage of a FET transistor as a consequence of interaction with a gas atmosphere.

  10. Structues basd on the field effect Mechanism of detection of hydrogen molecules and other hydrocarbons by a thick palladium gate.

  11. MOSFET arrays Nordic Sensor 4 MOSFET-s with cathalytic gate in a micromachined structure: 1 – MOSFET 2 – Al 3 – PECVD nitride 4 – LPCVD nitride Power consumption ca. 100 mW at 200oC.

  12. Organic composites Cyrano Sciences Sensor Technology Thin layer of a composite : conducting carbon in a polimer matrix

  13. Measurement with the help of sensor array Calculation block (microprocessor with software) Sensor 1 Calculated concentrations Gas mixture Sensor 2 Meter for measurements of CO and C3H8 concentrations in a mixture.

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