Sensor for High-Air-Humidity Measurement

  • V. Matko
  • D. Donlagic

Abstract

The humidity sensor using the sensitive capacitive-dependent crystal is described. Presented is the probe sensitivity (dependence of df on the dCx). In addition, the new idea of excitation of the entire humidity sensor with stochastic test signals is described, and the humidity surface-measuring method is given. It includes the influence of test signals on the weighting function uncertainty and on the A/D-D/A conversion. The results of humidity measurement with the excitation signals are shown experimentally. The uncertainty of the surface humidity measurement is less than 0.2% (T=15–25°C and humidity = 50 to 98%).

Keywords

Sensor Probe Humidity Sensor Excitation Signal Open Capacitor Humidity Measurement 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    K. W. Bonfig, Das Direkte Digitale Messverfahren (DDM) als Grundlage einfacher und dennoch genauer und störsicherer Sensoren, Sensor nov. 1988.Google Scholar
  2. 2.
    M. C. McGregor, J. F. Hersh, R. D. Cutkosky, F. K. Harris, F. R. Kotier, New Apparatus at the National Bureau of Standards for Absolute Capacitance Measurement, IRE Trans. Instr. 1–7 (3–4), 253–61 1958.CrossRefGoogle Scholar
  3. 3.
    A. M. Thompson, The Precise Measurement of Small Capacitances, IRE Trans. Instr. 1–7(3–4), 245–53 1958.CrossRefGoogle Scholar
  4. 4.
    C. Moon and C. M. Sparks, Standards for low values of direct capacitance, J. Res. NBS, vol. 41 pp. 497–507, nov. 1948.Google Scholar
  5. 5.
    G. L. Miller, E. R. Wagner, Resonant phase shift technique for the measurement of small changes in grounded capacitors, Rev. Sci. Instrum. 61(4) 1990, p. 1267.CrossRefGoogle Scholar
  6. 6.
    C. T. Van Degrift, Modeling of tunnel diode oscillators, Rev. Sci. Instrum. 52(5), 712–723, May 1981.CrossRefGoogle Scholar
  7. 7.
    H. Fischer, K. Heber, Industrielle Feuchtigkeitsmeßtechnik, expert verlag 1990, ISBN 3–8169-0610–9.Google Scholar
  8. 8.
    E. L. Nielsen, F. R. Landel, Mechanical properties of polymers and composites, by Marcel Dekker New York, 1994, ISBN 0–8247-8964–4.Google Scholar
  9. 9.
    A. Mouchtachi, R. El. Guerjouma, J. C. Baboux, Non Destructive Ultrasonic Evaluation of Fibrous Metal Matrix Composites, Kluwer Academic Publishers 1995, ISSN 0929–189X, p. 387–393.Google Scholar
  10. 10.
    E. Bartels, T. Funk, Correlation method for determination of the time constants of impedances applied to electrical model networks and to a liquid capacitor, J. Phys. E. 16 1983, p. 1105.CrossRefGoogle Scholar
  11. 11.
    U.K. Dmowski, A new correlation method for improvement in selectivity of bulk trap measurements from capacitance and voltage transients, Rev. Sci. Instrum. 61(4), April 1990, p. 1319–1325.CrossRefGoogle Scholar
  12. 12.
    V. Matko, D. Donlagic, Humidity measurement using the procedure of capacitive-dependent crystals, IMTC/95 Proceedings, Waltham, Massachusetts, april 24–26, 1995, ISBN 0–7803-2615–6.Google Scholar
  13. 13.
    V. Matko, D. Donlagic, J. Koprivnikar, Measurement of 0–1 ml Volumes Using the Procedure of Capacitive Dependent Crystals, IEEE Trans. IM Vol. 43 no 3, June ‘94.Google Scholar
  14. 14.
    V. Matko, D. Donlagic, J. Koprivnikar, Analysis of the Doppler signal by frequency modulation in ultrasonic flow measurement of fluids; System Analysis, Modelling, Simulation, vol 11–1993 (4), p. 313–323, ISSN 0232–9298.Google Scholar
  15. 15.
    W. Klanner, Ein kapazitives Messverfahren zur Bestimmung der Dicke von Flüssigkeitsfilmen, ATM (Archiv), Blatt V 1124–19 Nov. 1972.Google Scholar
  16. 16.
    E. Schrüfer, Elektrische Messtechnik, Carl Hanser Verlag München, Wien, 1984.Google Scholar

Copyright information

© Springer Science+Business Media New York 1997

Authors and Affiliations

  • V. Matko
    • 1
  • D. Donlagic
    • 1
  1. 1.Faculty of Electrical Engineering and Computer ScienceUniversity of MariborMariborSlovenia

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