Savkova T.N., Кravchanko A.I., Kuharenko S.N., Lukashov V.M., Svintitskij A.V.
THE DETERMINATION OF ENERGY AND OPTICAL CHARACTERISTICS OF THE MODEL OF LIGHTING DEVICE UNDER PULSE EXCITATION IN A MATHCAD SOFTWARE ENVIRONMENT ^{[№ 9 ' 2015]}
LED devices with a pulse mode are increasingly used in lighting technology — strobe lights, projectors, lights, security systems, sensors, pulse devices, etc. Pulsed power supply lets you reduce heat in the p-n junction of the LED, it improves efficiency and service life of the lighting device. There is a method to determine energy and optical characteristics of the LED model. Using lighting device under pulse excitation with proposed Mathcad software environmentallows to determine the current power consumption value of the model, the radiation power and energy efficiency. Measurements of energy and the optical parameters of the lighting device model manufactured by cold-white powerful LED ARPL-3W were made. It was shown that the maximum values of efficiency under pulsed excitation and continuous power for the model is amounted to about 40 %. The efficiency difference in power consumption (nominal mode) with continuous and pulsed excitation power with 50% duty cycle is about 5 %. In a range of wattages to 0,02 W efficiency lighting device model is practically independent of the crystal's active region temperature. The form of pulse supply affects energy efficiency of the LED depending model of lighting device. Exciting trapezoidal shapes of cold white LED triangular pulses makes efficiency lower than exciting those with rectangular shaped pulse. Studied power characteristics have shown a significant effect for the duration of the pump pulse currents exceed 2A efficiency of emitting recombination. Increasing the frequency of the supply current reduces the efficiency of the crystal under the same duration and power of the exciting pulse.

Savko E.S.
METHODIC OF STUDYING OF CONSUMERS’ BEHAVIOR ON THE MARKET OF MEAT FOODS ^{[№ 5 ' 2009]}
Determination of needs and wants of buyers becomes vitally important for enterprises functioning considering aggravation of competitiveness between producers of products. In this article the general stages, methods and approaches of studying of consumers’ behavior are determined, the matrix and questionnaire for studying of buyers’ opinions about products of meat markets are worked out here.