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Design of LISN artificial network for EMI measurement
Valúch, Ondřej ; Szabó, Zoltán (referee) ; Steinbauer, Miloslav (advisor)
Thesis is focused on the design, construction and understanding of LISN (Line Impedance Stabilization Network), or artificial mains network for EMI (Electromagnetic Interference) measurements. It discusses the concept of electromagnetic compatibility, why it is important to ensure it in equipment, what interference can be observed on the lines, and how to measure it. It also describes the function of the LISN, the requirements for its design according to the related standards and discusses its main parts. The design and the proposed components correspond to the work specification for the required network highest load. The transmissions of interfering signals through the filters were simulated on the designed network. The artificial network was constructed and the requirements for its parameters were measured. Functional verification was carried out on a known appliance.
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Analog and switching audio amplifier design and comparison
Leikep, Filip ; Roubal, Zdeněk (referee) ; Steinbauer, Miloslav (advisor)
The goal of this Bachelor thesis was to design and manufacture analogue audio-frequency amplifier working in class AB and switching amplifier in class D and measure differences between them. Analogue amplifier is designed using discrete components, simulations were done in Micro-Cap. Class D amplifier will be implemented using an integrated circuit. Further in the thesis an output USB sound card is designed. It is compatible with PC and mobile phone. Audio outputs are galvanically insulated from USB to prevent the formation of a ground loop. Soundcard has two line outputs and amplifiers for two pairs of headphones. It was also measured and compared with soundcard integrated in computer. Class AB amplifier together with soundcard were built into the aluminium box.
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Lead-acid baterry charger with automatic cycle
Moravec, Pavel ; Friedl, Martin (referee) ; Steinbauer, Miloslav (advisor)
The lead-acid batteries are still important and very often used type of battery even in 21st century. This project is focused on development of charger, which provides fast, but save charging of batteries with respect to maximum life time and reliability. The developed system uses constant current charging and constant voltage charging methods. It's specialized in charging batteries with liquid or gel electrolyte and traction types of batteries, which works with 12 V value of voltage. It's able to charge safely the deeply discharged batteries and when battery is unpluged for a long time, it can keep its capacity at maximum level too. The charger can choose optimal charging process according to the discharged level of battery. Each charging phase is interpreted by light signals and the achievable charging current is 20 A.
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Numerical modelling and measurement of the magnetic susceptibility in inhomogeneous materials by the NMR technics
Julínek, Michal ; Steinbauer, Miloslav (referee) ; Fiala, Pavel (advisor)
This bachelor work is concerned in magnetic susceptibility of specific object (glass cube filled with clay, with glass sphere in the centre). In the first part determining of magnetic susceptibility of object was carried out. Measuring was conducted on tomograph of ÚPT AV ČR. Method of gradient echo, which allows magnetic susceptibility determining of non-magnetic materials, was used. Distribution of magnetic field within the object was acquired (object was measured with and without sphere), the change of magnetic field (between object with and without sphere) was subsequently determined. In the second part, magnetic field simulation of the same object in the ANSYS software was performed. Calculation was conducted on 3D model by the finite element analysis. Distribution of magnetic field of object was acquired as a result of simulation. Results from simulation were compared with experimental findings.
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Optimization of the experimental NQR spectrometer
Segiňák, Ján ; Král, Bohumil (referee) ; Steinbauer, Miloslav (advisor)
The thesis deals with the NQR spectroscopy, which is one of the modern non-destructive measurement and diagnostic methods for the characterization of various materials. It is using a quadrupole moment - a property of atomic nuclei of certain isotopes. A method of nuclear quadrupole resonance (NQR) is in principle very similar to nuclear magnetic resonance (NMR). Thesis in the theoretical part analyse the principles of NMR and NQR, describes the possible use of this method to detect for example explosives, drugs, and other chemicals. In the following chapters are analysed the key parameters of NQR spectrometer and the principle of the chosen measurement method. The practical part deals with the individual components of NQR spectrometer, the design of possible improvements and programming of the measuring sequence. In the final chapter are processed the measurements of the submitted samples.
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Design measure amplifier for magnetic measurement
Hejtmánek, Tomáš ; Steinbauer, Miloslav (referee) ; Roubal, Zdeněk (advisor)
The purpose of this semester work is a design of a measuring preamplifier for a fluxmeter DTEE which is used for hysteresis loops on ferromagnetic materials measurements. Having respect to measure coils’ characteristics and processed voltage levels with ranges in nV and µV, there was necessary to investigate measure principles of such low voltage. And then choose an appropriate operational amplifier based on the result. Mainly with minimum input residual voltage and offset temperature dependency. Also was necessary to propose effective zero compensation and eliminate thermoelectric influence in the whole designed device. There was applied noise optimization of selected operational amplifier in PSpise software. The designed device will be assembled and tested. The given results will be evaluated together with possibilities of application for a measurement purposes in labs.
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Fast optical receiver for measurement application
Žádník, Jakub ; Steinbauer, Miloslav (referee) ; Drexler, Petr (advisor)
This bachelor's thesis analyzes the problem of a detection of analog optical signals on frequencies nearing 100 MHz. The theoretical part describes a principle of the basic photodiode types and their parameters including their equivalent circuit and parasitic characteristics. Next we discuss the ideal circuit selection and its components, especially the photodiode and operational amplifier. In the practical part we simulate the circuit in the software Tina-TI and measure chosen photodiodes. After that, real circuit boards are designed, constructed, soldered, tested and adjusted to achieve the best performance possible.
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Sources for electric fence
Surovec, Vojtěch ; Murina, Milan (referee) ; Steinbauer, Miloslav (advisor)
Bachelor’s project is divided to two parts. The First part is focused theoretically and the second part is focused practically. In the theoretically part we met the standartds of properties and application commercially avaible sources as well as of principle pulse (switch-mode) sources and circuit realization. In practically part is suggestion of circuit design and realization of source for electric fence, enebling becked up power 230 VAC / 12 VDC. The source have to contain control circuit for reliable function.
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