Osadchuk A.
Doctor of Technical Sciences, Professor, Head of Radioengineering Department,
Vinnitsa National Technical Universit, Vinnitsa, Ukraine
Osadchuk V.
Doctor of Technical Sciences, Professor, Prof. of Radioengineering Department,
Vinnitsa National Technical University, Vinnitsa, Ukraine
Osadchuk I.
PhD,
Researcher of Radioengineering Department, Vinnitsa National Technical
University, Vinnitsa, Ukraine
GAS CONCENTRATION TRANSDUCERS WITH FREQUENCY
OUTPUT SIGNAL BASED ON REACTIVE PROPERTIES
OF SEMICONDUCTOR STRUCTURES WITH NEGATIVE
DIFFERENTIAL RESISTANCE
Introduction. The characteristics of the transducers determine the accuracy and
reliability of control and regulation systems for process monitoring devices,
environmental characteristics, industrial plant safety, etc. Therefore, gas converters are
subject to stringent requirements. They should be economic, provide high accuracy of
measurement, have minimum dimensions, weight and energy consumption, be
compatible with modern computers and have the ability to manufacture on standard
integrated technology [1-4].
Currently, the existing semiconductor gas sensors do not meet the above
requirements. They have a low output signal, low accuracy and sensitivity, require
analog-to-digital converters and amplifiers for further signal processing. A promising
scientific direction, which allows to eliminate the disadvantages of existing analog gas
sensors, is the creation of converters that implement the principle of transformation
"gas concentration – frequency" on the basis of autogenerator semiconductor structures
with negative differential resistance.
Development of autogenerator gas transducers with a frequency output signal
requires knowledge of changes in the impedance of primary semiconductor gas
transducers from changes in gas concentration, that is, the gas reactive effect, because
these processes cause changes in the parameters of the oscillating circuit of
autogenerators, which in turn determines the dependence of the output frequency of
devices [5-8]. Thus, the work is devoted to the study of the mathematical model of the
gas reactive effect in semiconductor gas sensors, that is, the dependence of their total
output resistance on the gas concentration, which is determined by the processes on the
surface of the semiconductor.
- 485 -