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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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Gaussmeter design with three-axis measuring probe
Hejtmánek, Tomáš ; Novák,, Miroslav (referee) ; Roubal, Zdeněk (advisor)
The purpose of this work is the design of a gaussmeter with a three-axis probe for magnetic field mapping and subsequent reconstruction of the image using magnetic impedance tomography. Commercially available gaussmeters have low bandwidth for these purposes, and signals cannot be measured in synchronous detection mode. The aim of the thesis is select the most suitable magnetic field sensors for the MIT purposes and to design the entire measuring device to meet the measurement requirements in the wider frequency band and synchronous detection. Attention will also be paid to designing a suitable mechanical design of the probe and the location of the sensors. The proposed device will be tested and evaluated for MIT purposes.
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Analog-digital module for electrical impedance tomography
Zimniok, David ; Hejtmánek, Tomáš (referee) ; Mikulka, Jan (advisor)
Tato bakalářská práce se zabývá elektrickou impedanční tomografií a jejími problémy. Prvním problémem je měření napětí v širokém rozsahu od milivoltů po desítky voltů. Druhým problémem je měření fáze impedance pomocí mikroprocesoru bez lidské pomoci. Také bylo třeba vyřešit problém s návrhem elektrod a s přenosem malého napětí na velké vzdálenosti mezi měřeným objektem a navrženým zařízením pro zpracování signálů. Ke zpracování signálů a komunikaci byl zvolen mikroprocesor ARM doplněný o zesilovač, který má nastavitelné zesílení a také lineární optočlen pro ochranu mikroprocesoru. Pro zajištění přenosu měřeného napětí na velké vzdálenosti bez ztráty dat je navržena aktivní sonda. Data jsou přenášena prostřednictvím proudové smyčky.
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Laboratory current source with direct digital synthesis
Pěčonka, David ; Hejtmánek, Tomáš (referee) ; Mikulka, Jan (advisor)
The work deals with the design of a laboratory generator with a current output for supplying elements with a maximum impedance in units of k. The text itself discusses the designs of individual parts of the device and the choice of suitable components for their implementation. The sub-chapters deal with the design process of the power supply and digital parts are followed by the mechanical construction of the source, which ends with the verification of the expected properties of the designed and constructed source. The result of the work is a source with a current output of up to ±10 mA with the possibility of parameterization of the frequency, amplitude and shape of the signal using control elements and also digitally using the universal serial bus. The signal is generated using a direct digital synthesis (DDS) system. The generator itself is supplied by a rechargeable battery.
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Design Of The Pulse Generator For Testing And Validating Partial Discharge Measuring Systems
Hejtmánek, Tomáš
This article deals with the design and implementation of a pulse generator serving as acalibration generator for setting up measuring systems for monitoring the activity of partial discharges(PD) in the high-voltage power transformers or gas insulated switchgears (GIS). After installingthe measuring device, it is advisable to test the entire measuring chain and, if necessary, setparameters that would affect the correct detection of PD signals. Calibration pulse generators areused for setting and validating measuring chain. These are usually used in systems that sense theelectromagnetic activity of PD. Correct and timely detection of PD can avert a transformer accidentand thus contribute to higher safety in power plants. The proposed generator should serve as theoutput part of a programmable generator, which did not reach sufficient parameters of output pulses.The goal was to achieve a rising time around 100 ps and an amplitude of more than 6 V usingmodern and very fast operational amplifiers and step recovery diodes as a sharpener of the inputpulse. The measurements show waveform of the output voltage pulse.
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Design Of Measuring Amplifiers For Magnetic Measurement
Hejtmánek, Tomáš
The purpose of this paper is a design of a measuring preamplifier for a fluxmeter which was designed in Department of Theoretical and Experimental Electrical Engineering 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. 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 PSpice software. And in the last part of the paper will be show results of noise measurement on the amplifier. The given results will be evaluated together with possibilities of application for a measurement purposes in labs.
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Measured Parameters Of The Three-Axis Gaussmeter
Hejtmánek, Tomáš
The purpose of this article is a measuring parameters of a gaussmeter with a three-axis measuring probe designed for magnetic field mapping. Commercially available gaussmeters have low frequency bandwidth for these purposes, and signals cannot be measured in synchronous detection mode. Therefore, a suitable magnetic field sensor was selected and one channel of the device was designed and made. In particular, the higher bandwidth for three-axis measurement and the possibility of synchronous signal detection were taken into account. Attention will also be paid to designing a suitable mechanical design of the probe and the location of the sensors. The gaussmeter will be used for magnetic impedance tomography (MIT), which is reconstruction method of conductivity image. On the proposed device was performed measurements of frequency bandwidth, noise measuring of Hall probe and measuring constants of Hall generators. The properties were evaluated and compared with parameters of commercially available Gaussmeters.
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Gaussmeter With A Three-Axis Probe
Hejtmánek, Tomáš
The purpose of this article is the design of a gaussmeter with a three-axis probe for magnetic field mapping and subsequent reconstruction of the image using magnetic impedance tomography (MIT). Commercially available gaussmeters have low bandwidth for these purposes, and signals cannot be measured in synchronous detection mode. The aim of the paper is select the most suitable magnetic field sensors for the MIT purposes and to design the entire measuring device to meet the measurement requirements in the wider frequency band and synchronous detection.
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Gaussmeter design with three-axis measuring probe
Hejtmánek, Tomáš ; Novák,, Miroslav (referee) ; Roubal, Zdeněk (advisor)
The purpose of this work is the design of a gaussmeter with a three-axis probe for magnetic field mapping and subsequent reconstruction of the image using magnetic impedance tomography. Commercially available gaussmeters have low bandwidth for these purposes, and signals cannot be measured in synchronous detection mode. The aim of the thesis is select the most suitable magnetic field sensors for the MIT purposes and to design the entire measuring device to meet the measurement requirements in the wider frequency band and synchronous detection. Attention will also be paid to designing a suitable mechanical design of the probe and the location of the sensors. The proposed device will be tested and evaluated for MIT purposes.
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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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