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Electronic ballast for power LEDs
Vágner, Richard ; Martiš, Jan (referee) ; Červinka, Dalibor (advisor)
This diploma thesis deals with design of power LED driver. This driver contains electronic ballast circuits, converters, filters and control circuits. Overviews of circuits used in practice are listed along with analysis of power LED and considering options for selecting an appropriate design solution. Thesis describe principle of electroluminescense, creating of the device, its structure and problematics of current source supply. Including detailed overview of converters, ballasts and topologies used in lighting systems with the selection of a suitable solution for the final device with an output power of 50 W. The thesis contains cooling dimensioning for selected power LEDs, input circuit with EMI filter, bridge rectifier, boost converter and flyback converter with pulse transformer.
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Electronic ballast for power LEDs
Vágner, Richard ; Martiš, Jan (referee) ; Červinka, Dalibor (advisor)
This diploma thesis deals with design of power LED driver. This driver contains electronic ballast circuits, converters, filters and control circuits. Overviews of circuits used in practice are listed along with analysis of power LED and considering options for selecting an appropriate design solution. Principles of creating the device, structure and problems of current source are described in thesis. Including detailed overview of converters, ballasts and topologies used in lighting systems with the selection of a suitable solution for the final device with an output power of 50 W. The thesis includes cooling dimensioning for selected power LEDs, input circuit with EMI filter, bridge rectifier, boost converter and flyback converter with pulse transformer.
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Design and implementation of TEM cell
Bednarský, Vojtěch ; Růžek, Václav (referee) ; Dřínovský, Jiří (advisor)
The purpose is to design and make a TEM cell, which may often be referred to in publications as a Crawford chamber, after the inventor. The operating frequency is specified from 100 kHz to 400 MHz and is suitable for a test device of maximum size (0,3(l) x 0,3(w) x 0,1(h)) meters. I will first describe the basic methods of electromagnetic susceptibility testing, and electromagnetic interference measurements, and then mention the issues and motivations for the fabrication of the closed TEM cell. Computer simulations were performed in the numerical computing software CST Microwave Studio. The calculated dimensions were used as a starting point for simulation. Dimensions from the simulation were used for the fabrication of the closed TEM cell, which showed similar results as the results of the simulations.
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Language and content integration models in ELT
Synková, Blanka ; Gráf, Tomáš (advisor) ; Klégr, Aleš (referee)
The thesis focuses on the topic of language and content integration in ELT in a broad sense, i.e. it discusses not only CLIL but also other models of content-based teaching, viz. ESP (English for Specific Purposes), EAP (English for Academic Purposes), and EMI (English-medium Instruction). In the theoretical part of the thesis, these models are described as regards their history, typical features, teachers, learners, as well as benefits and negatives. The empirical part of the thesis explores the current practice of language and content integration at Czech general secondary schools ("grammar schools"). The research is based on case studies of five teachers who teach various courses belonging to this category. The preliminary research investigated what courses are currently being offered at grammar schools in Prague; they are mostly elective courses. Our research findings suggest that language and content integration in the form of elective courses is a rather common practice, although often unconscious. Teachers tend to act on the basis of their intuition rather than their knowledge of theory and practice of language and content integration. Generally, it seems that more emphasis is put on content than language in these lessons. Content-based English lessons may be beneficial for learners for...
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Antenna Preamplifier For Emi Measurements
Sedlák, Milan
The contribution deals with the design of a low-noise amplifier with frequency band from 30 MHz to 1 GHz, usable for measuring and testing electromagnetic interferences in EMC test room. The main task of the low-noise amplifier is to improve sensitivity of the measurement chain which allows measurement of the undesired emission of high frequency signals at a very low power level.
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Language and content integration models in ELT
Synková, Blanka ; Gráf, Tomáš (advisor) ; Klégr, Aleš (referee)
The thesis focuses on the topic of language and content integration in ELT in a broad sense, i.e. it discusses not only CLIL but also other models of content-based teaching, viz. ESP (English for Specific Purposes), EAP (English for Academic Purposes), and EMI (English-medium Instruction). In the theoretical part of the thesis, these models are described as regards their history, typical features, teachers, learners, as well as benefits and negatives. The empirical part of the thesis explores the current practice of language and content integration at Czech general secondary schools ("grammar schools"). The research is based on case studies of five teachers who teach various courses belonging to this category. The preliminary research investigated what courses are currently being offered at grammar schools in Prague; they are mostly elective courses. Our research findings suggest that language and content integration in the form of elective courses is a rather common practice, although often unconscious. Teachers tend to act on the basis of their intuition rather than their knowledge of theory and practice of language and content integration. Generally, it seems that more emphasis is put on content than language in these lessons. Content-based English lessons may be beneficial for learners for...
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Electromagnetic compatibilty
Šimoník, Martin ; Hoder, Karel (referee) ; Havlíková, Marie (advisor)
This bachelor is focused on a problem field of electronic compabiliti as the technical side as same as biological side of it. This Thesis describes the basic concepts of EMC and also analyzis each legislative requirements and regulations of EMC. One part of this thesis include designing a test procedur for verifcation of EMC pressure measurement technology of BD SENSORS company and realization of it.
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Electromagnetic compatibility tests
Kolařík, Jan ; Hoder, Karel (referee) ; Havlíková, Marie (advisor)
The aim of this bachelor project is analysis problems branch of science EMC. The bachelor project contains basic distribution field and description individual parts of the field. Next bachelor project contains detailed description of individual measuring devices and equipment test room of EMC in company AEV s.r.o. like are signal generator, spectral analyzer and antennes. Last part of bachelor project deals with measurement electromagnetic interference on the product from the company AEV s.r.o. in accordance with the standard TL965 and design report of tests for a customer.
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Laboratory Switching Power Supply
Šneidr, Radim ; Petržela, Jiří (referee) ; Šebesta, Jiří (advisor)
The topic of my bachelor´s thesis is a solution to a laboratory switching power supply, look at their benefits, disadvantages and characteristics in terms of EMI. The aim this work is also to design the concept of two outputs switching supply with monolithic circuit, LM2576 with the inclusion of a current limiter and implementation of a test version which will use basic measuring. Further, design a general scheme and the mechanical solution of a power supply including measuring modules. Design layout of printed circuit, complemented with thorough testing.
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Ultra low noise switching power supply
Raba, Jaroslav ; Leuchter,, Jan (referee) ; Šrámek, Petr (advisor)
This thesis deals with the issue of switching power supply in terms of noise ratios in the output voltage. In the theoretical part analyzes the basic principle of classical and resonant topology switching power converters in terms of output voltage ripple and switching noise. There are also some possibilities of compensation to minimize switching noise and output ripple. The second part describes the custom design a low noise switching power supply, which is composed of an active power factor corrector, power converters and ripple limiter. The main power converter is designed as an LLC resonant converter. The last part deals with the actual construction of the proposed source, its measurement and presentation of the results.
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