Vol 3, No 11 (2015)

The article deals with with the designing of a laboratory work "Generators of Harmonic Oscillations" for the course of "Fundamentals of Circuitry of Telecommunication Devices". The use of laboratory benches and comparison of the results of full-scale and model experiments are considered.

To identify malfunctions in mobile cellular systems, a model of expert system with fuzzy logic is considered. The authors demonstrate an implementation of the expert system module by identifying of insulation resistance malfunction of the cellular communication cable. The application of fuzzy logic for a knowledge base creation enables us to formalize the assessment of object technical condition and reasonably make decisions on malfunction identification.

The study focuses on the influence of the processing quality of 4H-SiC plate surfaces on the speed of thermal oxidation of silicon carbide in dry oxygen. The surfaces of plates with a bigger roughness demonstrate thicker oxide film under otherwise equal conditions.

The article presents an analysis of popular photolithographic methods of the formation of small-size elements on the substrate surface by using of double photoresist exposure obtained by imposing of photoresist layers and masks. The shortcomings of the methods are pointed out. In this connection, an improved scheme of photolithography technological process is suggested. It allows avoiding the shortcomings and obtaining small-size elements of less than 1 mcm.

A simulation of serial group connection of power semiconductor devices at various values of the parameters of snubber circuits is carried out. Conclusions are made about the possibilities of optimizing of the parameters of snubber circuits.