The effect of generation rate on transient photoconductivity of semi-insulating (SI) 4H-SiC is discussed. The rate of generation of electron–hole pairs is dependent on the number of photons incident on the sample material and its absorption and reflection coefficients. The number of photons and their energy is dependent on the radiation power and wavelength of the light source illuminating the material. The results of research, obtained with a specialized simulator, present the influence of changes in the filling of individual defect centres’ levels on changes in conductivity of the test material observed after switching on the photoexcitation. For the purpose of simulations, presented is a versatile model of semiconductor material. It encompasses six point defects that appear in SI 4H-SiC materials the most often. Those defect centres correspond to Z_1/2 recombination centre, deep electron and deep hole traps, nitrogen-related shallow donors of two kinds and a boron-related shallow acceptor. The simulation results can be used to design and determine properties of photoconductive switches.

The paper presents issues related to the analysis of electricity quality of in a public building. The effects related to the occurrence of disturbances in the electrical installation and the benefits of using a energy monitoring system were presented. The results of measurements of electric energy quality parameters for a selected public utility object are presented.

The procedure for determination of trap parameters by photo-induced transient spectroscopy is based on the Arrhenius plot that illustrates a thermal dependence of the emission rate. In this paper, we show that the Arrhenius plot obtained by the correlation method is shifted toward lower temperatures as compared to the one obtained with the inverse Laplace transformation. This shift is caused by the model adequacy error of the correlation method and introduces errors to a calculation procedure of defect center parameters. The effect is exemplified by comparing the results of the determination of trap parameters with both methods based on photocurrent transients for defect centers observed in tin-doped neutron-irradiated silicon crystals and in gallium arsenide grown with the Vertical Gradient Freeze method.