Technology, energy, agriculture transport AIC

Oleksandr Vozniak – сandidate of Science (Engineering), Associate Professor of the Department of Electric Power Engineering, Electrical Engineering and Electromechanics of Vinnitsia National Agrarian University (3 Soniachna St., Vinnitsa, 21008, Ukraine, email: alex.voz1966@gmail.com).
Andrii Shtuts – Assistant Professor, Department of Electric Power Engineering, Electrical Engineering and Electromechanics, Vinnitsia National Agrarian University (3, Solnechna str., Vinnitsia, 21008, Ukraine, email: shtuts1989@gmail.com).

Improving the performance of microwave devices can be achieved both through the use of a fundamentally new element base, and through the use of new circuit designs. In this respect, the direction of use of the reactive properties of transistors as well as transistor structures with negative resistance for the construction of information-measuring systems and operating and computing devices of the microwave range is promising in this respect.
In order to confirm the proposed methods, it is necessary to compare the results of the experimental studies using the proposed methods and means of measuring the W-parameters of real potentially unstable four-poles. As such four-poles it is proposed to use bipolar and transistors with a wide range of frequencies of potential instability. The paper develops mathematical models of W-parameters of such structures and evaluates their parameters in the frequency range.
The active four-pole is a transistor model. Its W parameters can be determined either experimentally - for specific conditions or calculated - by using a physical transistor replacement circuit. In most cases, the calculation path is more acceptable because it allows to obtain analytical expressions for the four-pole, it is important in the analysis of the influence of various factors on the characteristics of the scheme under study.
The inertial properties of the transistor are already manifested at relatively low frequencies and must be taken into account in practically the entire operating range of the transistor. The theoretical model holds up to frequencies f  2fт (where ft is the limit frequency) [1,3]. At higher frequencies, it is necessary to consider the parasitic reactive parameters of real transistors, first of all, the inductance of the terminals.
A physically T-equivalent equivalent transistor replacement scheme was proposed by Pritchard in a simplified version [4]. It has several varieties, differing in the configuration of the circuit consisting of the resistance of the base material and the capacity of the collector junction. If we carefully consider and compare the T and U-shaped circuits of the transistor substitution, it can be noticed that they differ only in the configuration of their inne    r part - the theoretical model. At high frequencies P and T, such circuits are not exact mutual equivalents. This is due to the approximation used in the transition from one circuit to another. However, the frequency characteristics of the circuits are very close. Each of them models the processes in the transistor with approximately the same accuracy, and in this sense they are equivalent.

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