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Fluxmeter with graphical display of B-H curve
Ježek, Jaroslav ; Mačák, Jaromír (referee) ; Hanák, Pavel (advisor)
This work deals with simple fluxmeter which is able, together with other device, to show hysteresis loop. Hysteresis loop is a graphic expression of dependence of magnetic induction on intensity of magnetic field. Oscilloscope is used to display the hysteresis loop. This device is fully sufficient for the display. The measured objects are solenoids from various kinds of materials with the same shape. The main aim of this work is the design, realization and description of the fluxmeter. The fluxmeter consists of several partial blocks. The first one, on which this work is focused, is signal generator which is able to generace different kinds of signal. The generated signal comes on primary winding of solenoid where a magnetic field on a given intensity rises. An amplifier is used to obtain the sufficient intensity. Next thing this work is focused on is the design of the integrator which is necessary for the correct function of the fluxmeter. As suggested, there is shown the block diagram of linking of individual parts. There are described the measured results at the end of this work.
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Electromagnetic interference and pacemakers
Kulík, Jindřich ; Richter, Miloslav (referee) ; Havlíková, Marie (advisor)
This thesis deals with electromagnetic compatibility of implantable electro-medical devices using in cardiology. The main aim of this thesis is detection of the resistance of implantable pacemakers (PM) and implantable cardioverter defibrillators (ICD) to the electromagnetic interference. In the first part of this thesis, a function of the heart, which is necessary for understanding of PM and ICD operation, is described. The function and construction of PM and ICD is detailed in the theoretical part as well. The next part is focused on the electromagnetic compatibility. The next part is description of the measurement method and the experimental arrangement used for practical experiments with electromagnetic resistance of PM and ICD.
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Reconnection of magnetic field and consequences in plasma astrophysics
POKORNÝ, Jan
The topic of presented bachelor thesis is the description of the effect called reconnection of magnetic field. The first part describes the theory of plasma and magnetic field generally. Second chapter shows plasma behavior in the magnetic fields. Then, the attention is paid to the effect of reconnection of magnetic field and its numerical modelling. Further the influence of this effect on processes in astrophysical plasmas is described, especially the mechanism of reconnection of magnetic field on Sun and in our Galaxy. The last part shows a theoretical research of the possibility of triggering of magnetic reconnection by MHD oscillations and plasma waves and the inverse process of reconnection of magnetic field as a process which generate the plasma waves.
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Diagnostics of Breakdown in Electric Arc Exposed to External Magnetic Field
Hlína, Jan ; Šonský, Jiří
An arc in external magnetic field acquires a helical shape and when the magnetic field exceeds a critical value the arc starts to oscillate. The oscillations may lead to many types of shortenings (breakdowns) between the adjacent windings of the arc path. We have investigated experimentally the steepness of the voltage fall reflecting the breakdown and the influence of mean arc voltage and electrode polarity on this characteristic.
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Porovnání magnetického pole vně a uvnitř trolejbusu 21 Tr řízeného GTO nebo IGCT tyristorem
Nečesaný, Jakub ; Doležel, Ivo
This work is focused on the magnetic field modelling and analysis inside the trolley bus 21TR. Mathematical description is presented. Computation is carried out for accelerating regime for application of two different power switching semiconductor devices GTO and IGCT. Study of the magnetic field is done for head level of standing and sitting people. Local maximum of the magnetic field is also determined. Differences between magnetic field levels given by GTO and IGCT power switching semiconductor devices are consecrated. Finally, geometrical convergence of this problem is evaluated
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