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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Využití termochromních systémů pro testování distribuce tepla / Using thermochromic systems for testing heat distribution

Klimeš, Jan January 2017 (has links)
This thesis deals with principles of thermochromism and its possible applications in heat distribution testing. Theoretical part describes mechanisms which allow the thermochromic properties of the substances. Particular attention is paid to cholesteric liquid crystals. Ability to measure the heat for this type of liquid crystals was varified. Also long service life in high humidity environment, enviroment with intense UV radiation, cyclic changes in temperature or immersion in water was tested. A possibility of their practical use in diagnosis was verified as well. Specifically mapping of heat distribution on an assembled PCB. Conclusion contains comparison and evaluation of this method in terms of accuracy, user comfort and economic advantages compared to conventional infrared sensors.
112

Zařízení pro automatické měření voltampérových charakteristik / Device for automatic measurement of volt-ampere characteristics

Ondráček, Petr January 2020 (has links)
The Master's thesis discusses the design and realization of electronic meter of volt-ampere characteristics using Wifi module ESP32. The device is designed to be able to measure the characteristic in the voltage range of +/- 20 V and current range of +/- 200 mA. The device is controlled by web interface. The user is able to connect to it with for example his or her smartphone. This interface enables the user to configure various parameters, including the range of measurement and the power restriction. Furthermore, it is possible to graphically display the measured characteristic and export the data. To be independent on the outer network, the ESP32 is operated as an access point, which is creating a new simple network without the internet connection. In the Master's thesis, the principle of voltage and current measurement is explained theoretically, the circuit connection of device and the printed circuit board are designed and the cover of the device is modeled. Also the process of creating the device according to the design is described and the cover of the device is printed on 3D printer. After that, the control program is designed, described and uploaded into the resulting device. Finally, the functionality of the device is tested by measuring the volt-ampere characteristics of a few components.
113

Vestavěná řídicí jednotka pro ovládání laboratorního zařízení / Embedded Control Unit for Instrumentation of Laboratory Appliance

Voda, Zbyšek January 2020 (has links)
Aim of this thesis is modular design of control system for Golem device, which is used for drug research. Several modules with specified controlled area were designed. They communicate using CAN bus and are controlled by Raspberry Pi computer. The thesis includes PCB design and control firmware for modules, backend application for Raspberry Pi, which provides application interface, and simple protocol used for communication between modules. Designed system was tested in simulated environment.
114

Měnič s tranzistory GaN pro elektrický kompresor / Inverter for electric supercharger with GaN transistors

Galia, Jan January 2021 (has links)
This master’s thesis deals with the design and realization of a functional sample power inverter for an electric compressor, which is used in hybrid cars. The electric compressor powered by the inverter is E-compressor by Garrett Advancing Motion. An inverter will be using modern High Electron Mobility Transistors which are based on gallium nitride (GaN). The purpose of this thesis is to find if GaN transistors can be used in E-boosting application.
115

Hodnocení materiálových a procesních faktorů na DPS metodou smáčecích vah / Wetting Balance Method - Evaluation of PCB Material and Process Factors

Chloupek, Tomáš January 2009 (has links)
This work deals with issues of the wetting forces during soldering and evaluates material and procedural effects on the soldering process. The aim is to set the technology operations to get best quality of soldered joints.
116

Logistika a zásobování v opravně základových desek plošných spojů pro notebooky / Logistics and supply of PCB for repair of notebooks

Grob, Filip January 2010 (has links)
This diploma thesis deals with issues of inventory management and logistics controlling. These segments are one of most important instruments used in logistics. Theory of these logistic instrumens are used as a base for practical part of this diploma thesis, where is described and suggested methodology for inventory management of printed circuit board in repair center. This buffer inventory serves for securing performance of customer’s supplies in case of failure on repair line. Thereinafter is realized program in MS Excel interface for supplying leadership with main insistence to prevent order delay.
117

Emulátor 3.5“ disketové mechaniky pomocí RS232 a SD paměťové karty / Emulator of 3.5" diskette drive using RS232 and SD memory card

Sedláček, David January 2012 (has links)
This thesis deals with the design of the 3,5" floppy drive emulator with ATMEGA microprocessor unit. The emulator has been designed according to the principles of designing electronic devices, there is also object-control application and firmware for a microcontroller, which supports MFM coding. The thesis also lists all the formats of data stored or transmitted along with some flowcharts.
118

Návrh a sestavení spínaného zdroje o výkonu 2,5 kW / SMPS design and assembly with an output of 2.5 kW

Pospíšilík, Vojtěch January 2014 (has links)
This diploma thesis describe the desing and assembly of switching power supply with an output of 2,5kW. At first is described the funcional principle of SPMS. The next is the proceed design of power part of the converter composed from calculation of transformer, inductors, capacitors and sizing of semiconductors. There is proceed the calculation of power looses. The next step is to make acquaintance with the possibilities of feedback control, creating a model system for simulating and executing the selection of an appropriate regulatorystructure.The following is the calculation of regulators suitable method and simulation at program MatlabSimulink. Is procced the computing and realization of regulators and finding the PWM modulator. At over is constution of contorl logic and desin of printed circuit desing, assembly and their recovery.
119

Studie operativního řízení výroby ve vybrané firmě / The Study of Operational Production Management in Selected Firm

Drga, Miroslav January 2012 (has links)
The thesis is focused on optimizing of operational management to maximize efficiency of production capacity in Production plant Brno. This is an analysis of the current state which poiting on inprovable weak spots. They are mounting machines and company information systém. Results of this thesis are concepts which should leads in more effective operational management.
120

Improving jet printing quality for printed circuit boards : Optimizing first dot jetting deposition through experimental design and response surface methodology

Hedlund, William, Sjöberg, Gustav January 2023 (has links)
Printed circuit boards (PCBs) are essential components in various electronic devices, playing a vital role in their functionality. Over time, PCBs have evolved significantly, becoming smaller, more complex, and multi-layered to meet the demands of advancing technology and consumer preferences. The quality of solder paste deposits is measured by circularity, volume, positioning, and the number of satellites. Mycronic is a supplier of jet printing machines for PCB manufacturers and needs to investigate and counteract an unwanted variation in volume and positioning within the first dot of the solder paste strip, and its so-called “sea saw” effect for the following three dots.  This master’s thesis has two aims. The first aim is to develop and evaluate an experimental method to reduce variation between the dots in the strip. The second aim is to reduce the variation between the 1st dot and the following three dots by finding a combination of pre-feed, first, second, and third waveforms to obtain improved precision, volume, circularity, and reduced volume variation. Using an experimental design a full factorial design was used, examining six experimental factors. The design was further augmented with a central composite design to describe the second-order model. The knowledge from the experiment was used to optimize and improve the quality factors of jet printing, which were verified with an additional experiment. The results of the study provided compelling evidence that only the selected experimental factors had a significant impact on improving the volume metric. It was observed that the presence or absence of satellites during the experiment did not have any effect on the results, and neither did the positioning and circularity factors contribute to any improvement or deterioration. Specifically, the most significant difference in volume between 1st and following three dots for the optimized solution is 0.5 nl, and the currently used settings have a difference of 2.65 nl. The experimental approach employed in this master's thesis holds excellent promise for Mycronic, as it paves the way for the future development of piezo-actuation profiles (i.e. specific settings for the jet printer). The potential contributions to the industry are significant, particularly in terms of advancing the methodology for investigating and enhancing the quality metrics of piezo-actuation profiles through experimental means. This research opens up new avenues for Mycronic to refine its printing processes and improve overall print quality, ultimately leading to better outcomes for their customers.

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