|
|
Portable source for induction heating
Nevřela, Tomáš ; Martiš, Jan (referee) ; Knobloch, Jan (advisor)
The aim of this work is to realize and test a prototype portable source for induction heating of small parts. The project contains a theoretical basis of resonant circuits and induction heating. The device design is based on simulation results from the FEMM program, with which a focussing coil for induction heating has been designed. The parts of the thesis are the realization of the designed device, its putting into operation and the programming of the control.
|
|
|
Induction heating for small applications
Hrbáč, Lukáš ; Foral, Štěpán (referee) ; Krbal, Michal (advisor)
This bachelor’s thesis covers the topic of induction heat and possible solutions for small applications. There is theoretical knowledge needed for design of an induction device and also principles of induction heat. In the thesis, there is described resonant circuit, which is the main part of induction heating device. Furthermore, usual interpretations of driver and power circuits are analyzed. This work describes different ways how to adjust operating frequency to achieve better results. This thesis also includes verification of functionality of such a device, measurement of operating parameters and efficiency. Instructions for laboratory exercise dealing with induction device are attached in the appendix.
|
|
| |
|
|
Laboratory device involving the high selectivity filters
Tuhý, Luboš ; Kovář, Jan (referee) ; Petržela, Jiří (advisor)
This project deals with the frequency filters of high selectivity. The area frequency filtering is fairly comprehensive and theoretically demanding discipline. The aim of this work isn’t to describe in detail and to include knowledge of the frequency filters, but only to clarify the aforementioned issues. In particular, we focus practically on filters working on other physical principles, especially on the crystal structure of partition filters and ceramic filters. The circuit simulation programs through classes Spice will be one of the parts of the theoretical analysis. There will be presented various options for implementing these filters, and the test products used in the design. The laboratory exercises dealing with frequency filtering and measuring engineered product will be made and based on the theoretical findings of this work. The laboratory exercises will include the developing of the model protocol.
|
|
|
Switch stereo low frequency signals
Lukesle, Václav ; Jankovský, Jaroslav (referee) ; Hejátková, Edita (advisor)
The work proposes steps for fabricating low-frequency preamplifier including switchable inputs and the output equalizer. In the beginning of the thesis theoretical principles of amplifying the low-frequency signals are introduced. For setting the resonance frequency of equalizer the gyrator filter has been used. By setting the aforementioned frequency and tuning the potentiometer we are able to change the quality factor as well as the gain of the entire circuit. Benefit of this work is a large flexibility for tuning the output signal including a possibility of selection of four various inputs. Simulation and measurement results, PCB and a summary of discrete components are finally attached.
|
|
|
Portable source for induction heating
Nevřela, Tomáš ; Martiš, Jan (referee) ; Knobloch, Jan (advisor)
The aim of this work is to realize and test a prototype portable source for induction heating of small parts. The project contains a theoretical basis of resonant circuits and induction heating. The device design is based on simulation results from the FEMM program, with which a focussing coil for induction heating has been designed. The parts of the thesis are the realization of the designed device, its putting into operation and the programming of the control.
|
|
|
Power amplifier for shortwave radioamateur bands
Smutný, Štěpán ; Šebesta, Jiří (referee) ; Lukeš, Zbyněk (advisor)
The amplifier is designed in the class AB, for which is typical acceptable efficiency and relatively low quiescent power consumption. As active components, the MOSFETs transistors are used. Their quadratic transfer characteristic allows for a gain control by means of quiescent current setting. The principle of MOSFETs function will be described, along with their utilization in the class AB amplifier. Since the amplifier processes signals in the shortwave band, parasitic capacitances of the transistors reduces gain greatly. Therefore, these capacitances will have to be compensated by positive feedback. First, the function of the amplifier will be verified in PSPICE program, then design or selection of real components (including transformers, heat sink and bias control) will be carried out. By performing measurement on assembled amplifier, we have verified the gain control (doubling the quiescent current increases gain by 3dB). If the quiescent current is set to 1250mA, the gain exceeds 20dB in the range from 1.4MHz to 13.5MHz. Gain at high frequencies was achieved thanks to compensation by positive feedback.
|
|
|
Induction heating for small applications
Hrbáč, Lukáš ; Foral, Štěpán (referee) ; Krbal, Michal (advisor)
This bachelor’s thesis covers the topic of induction heat and possible solutions for small applications. There is theoretical knowledge needed for design of an induction device and also principles of induction heat. In the thesis, there is described resonant circuit, which is the main part of induction heating device. Furthermore, usual interpretations of driver and power circuits are analyzed. This work describes different ways how to adjust operating frequency to achieve better results. This thesis also includes verification of functionality of such a device, measurement of operating parameters and efficiency. Instructions for laboratory exercise dealing with induction device are attached in the appendix.
|
|
|
Laboratory device involving the high selectivity filters
Tuhý, Luboš ; Kovář, Jan (referee) ; Petržela, Jiří (advisor)
This project deals with the frequency filters of high selectivity. The area frequency filtering is fairly comprehensive and theoretically demanding discipline. The aim of this work isn’t to describe in detail and to include knowledge of the frequency filters, but only to clarify the aforementioned issues. In particular, we focus practically on filters working on other physical principles, especially on the crystal structure of partition filters and ceramic filters. The circuit simulation programs through classes Spice will be one of the parts of the theoretical analysis. There will be presented various options for implementing these filters, and the test products used in the design. The laboratory exercises dealing with frequency filtering and measuring engineered product will be made and based on the theoretical findings of this work. The laboratory exercises will include the developing of the model protocol.
|
|
|
Switch stereo low frequency signals
Lukesle, Václav ; Jankovský, Jaroslav (referee) ; Hejátková, Edita (advisor)
The work proposes steps for fabricating low-frequency preamplifier including switchable inputs and the output equalizer. In the beginning of the thesis theoretical principles of amplifying the low-frequency signals are introduced. For setting the resonance frequency of equalizer the gyrator filter has been used. By setting the aforementioned frequency and tuning the potentiometer we are able to change the quality factor as well as the gain of the entire circuit. Benefit of this work is a large flexibility for tuning the output signal including a possibility of selection of four various inputs. Simulation and measurement results, PCB and a summary of discrete components are finally attached.
|
guest ::
