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Electric Circuits and Components
Published in Quamrul H. Mazumder, Introduction to Engineering, 2018
An inductor is a circuit component that is made of a conducting wire wrapped around a core in the form of a coil. In fact the circuit symbol of an inductor, as shown in Table 8.1, looks like a coil. There are different types of inductors that can be categorized based on the material composition of their cores, as shown in Figure 8.1b. The core can be made of iron or ferrite, air, or any nonmagnetic material. Iron core inductors are generally used in power supplies. Ferrite core inductors are heavily used in applications that operate with high frequencies. Air or nonmagnetic core inductors are widely used in filtering circuits, in combination with resistors, or capacitors, or both, depending on the filter design. Unlike capacitors that block abrupt change in voltage, inductors prevent instantaneous change of current in a circuit.
F
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
fenestration fenestration any opening or arrangement of openings (normally filled with media for control) for the admission of daylight. frequency independent antenna antenna with very large bandwidths. Upper frequency can be about 40 times higher than the lower frequency. Examples: spiral and log periodic antennas. Ferranti, Sebastian Ziani de (1864-1930) Born: Liverpool, Lancashire, England Best known for developing systems of highvoltage AC power systems. The generating and transmission systems he designed still form the basis for most modern power systems. As a principal in the London Electric Supply Corporation, Ltd., Ferranti demonstrated that high-voltage AC current could be distributed and then stepped down for use in a more efficient and economical system than the smaller DC current systems then operating. Ferranti invented a number of other devices and systems as a consultant and in his own company. He was named president of the Institute of Electrical Engineers in 1911. ferrite a term applied to a large group of ceramic ferromagnetic materials usually consisting of oxides of magnesium, iron, and manganese. Ferrites are characterized by permeability values in the thousands and are used for RF transformers and high Q coils. ferrite beads small toroids made of ferrites which are slipped over a conductor in order to suppress RF currents. The beads act as RF chokes at high frequencies. ferrite core a magnetic core made up of ferrite (compressed powdered ferrromagnetic) material, having high resistivity and low eddy current loss. ferrite core memory memory. See magnetic core Its properties can be altered when an external magnetic field is applied. It is used in ferrite loaded loop antennas, for example, to increase the flux through the loop antenna. ferroelectric material a polar dielectric in which the crystallographic orientation of the internal dipole moment can be changed by the application of an electric field. ferrofluid iron based solution employed in voice coil/pole piece gap improving magnetic flux and power handling capacity. ferromagnetic materials in which internal magnetic moments spontaneously line up parallel to each other to form domains, resulting in permeabilities considerably higher than unity (in practice, 1.1 or more); examples include iron, nickel, and cobalt. ferroresonance a resonant phenomenon involving inductance that varies with saturation. It can occur in a system through the interaction of the system capacitance with the inductance of, for example, that of an open-circuited transformer. Ferroresonance resembles, to some extent, the normal resonance that occurs wherever L-C circuits are encountered. If the capacitance is appreciable, ferroresonance can be sustaining or result in a limited over voltage enough to damage the cable or the transformer itself. ferroresonant transformer a transformer that is designed to operate as a tuned circuit by resonating at a particular frequency. Fessenden, Reginald Aubrey (1866-1932) Born: East Bolton, Quebec, Canada Best known as a radio pioneer who described the principle of amplitude modulation and the heterodyne effect. Fessenden became the chief scientist at Edison's laboratory and then spent two years with Westinghouse. He later held teaching posts at Purdue University and Western University of
Design and Analysis of quasi Resonant high gain Impedance source DC-DC converter for DC microgrid
Published in International Journal of Electronics, 2023
Harinaik Sugali, Shelas Sathyan, N. J. Merlin Mary
The HFT and coupled inductor are designed by using EE25 and EE42 ferrite core respectively. Here, Litz wires are used to reduce losses associated with high frequency operation. This converter’s gate pulses are generated using TI-supported TMS320F28335 DSP with a C2000 development kit. The gate pulse of the converter with a small shoot through duty (=0.15) at full load (=150 kHz) and half load (=145 kHz) is depicted in Figure. 10. The designed hardware prototype is tested with constant shoot through duty () of 0.15 and variable input voltage of 36V - 60V at different load condition. Here, the output voltage is regulated at 380V by varying the switching frequency between 90-215kHz. For a 60V input, converter is operated at 90kHz and for 36V it operates at 215kHz.
Design and analysis of isolated high step-up Y-source DC/DC resonant converter for photovoltaic applications
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Harinaik Sugali, Shelas Sathyan
The experimental results of a 200W hardware prototype developed in the laboratory are presented in this section. The photograph of the developed prototype is shown in Figure 11. A 335W single PV panel is connected to feed power to the converter. The specifications of the converter and design parameters are given in Table 2. The active switches and other passive components are chosen to attain lower conduction losses at all operating conditions. The EE42 ferrite core is selected for the design of coupled inductor. It is tightly coupled and connected in a Y-shape manner. All three windings are wound on the same bobbin. The EE25 ferrite core is used for HFT. The high-frequency transformer and coupled inductor are wound with Litz wire to minimize the skin effect and associated losses. The hardware prototype has been validated and tested at a standard irradiation condition where the supply voltage is 40 V. The MOSFETs gate signals are generated using the C2000 Texas Instruments (TI) supported (TMS320F28335) DSP development kit. MIC4451 driver IC, 7407 buffer, 6N137 optocoupler, and auxiliary power supply are used for the isolated gate driver circuit. The experimental waveforms have been found to resemble the expected steady-state operational waveforms very closely.
Characteristics of Eddy Current Attenuation in Double-Layer Metallic Plate and Measurement of Gap Thickness
Published in Research in Nondestructive Evaluation, 2023
Jing He, Zhiwei Zeng, Jiayi Li, Yanfei Liao, Chenhao Zhang
The test plates include two monolithic plates of different thicknesses, two double-layer plates with different gap thicknesses and a clad plate that does not have air gap between the layers. Figure 1 shows the geometric models of the plates. The conductivities of the monolithic plates and the top layers of the double-layer plates and the clad plate are denoted as σ1 and the conductivities of the bottom layers of the double-layer plates and the clad plate are denoted as σ2. Define k as the ratio of σ2 to σ1. A reflection probe is designed, as shown in Figure 2. The excitation coil of 100 turns is inside, and the reception coil of 260 turns is outside. The excitation coil generates primary magnetic field and induces EC in the test plate and the reception coil senses the magnetic field including the secondary magnetic field generated by the EC. The ferrite core has a relative permeability of 650, and its conductivity is assumed to be 0. The liftoff which is the distance between the probe and the plate is 1.0 mm. The frequency is varied from 1 kHz to 300 kHz to study its effect on the EC distribution in the test plate.