The General Class Question Pool 2011-2015 Study Notes
... An amateur station may transmit communications in which the licensee or control operator has a pecuniary (monetary) interest only When other amateurs are being notified of the sale of apparatus normally used in an amateur station and such activity is not done on a regular basis. All of these choices ...
... An amateur station may transmit communications in which the licensee or control operator has a pecuniary (monetary) interest only When other amateurs are being notified of the sale of apparatus normally used in an amateur station and such activity is not done on a regular basis. All of these choices ...
Topic 2 Green-Mode Power by the Milli-Watt
... over fixed frequency CCM and DCM designs. The price for saving the MOSFET turn-ON loss and the output rectifier reverse recovery loss is that the switching frequency must vary in order to maintain valley switching. What happens to the switching frequency of the QR flyback converter when the input vo ...
... over fixed frequency CCM and DCM designs. The price for saving the MOSFET turn-ON loss and the output rectifier reverse recovery loss is that the switching frequency must vary in order to maintain valley switching. What happens to the switching frequency of the QR flyback converter when the input vo ...
S2014, BME 101L: Applied Circuits Lab 5a Characterizing
... At that resonant frequency, even small currents produce large motions of the voice coil, in turn producing large voltages—that is, the impedance at that frequency is large. We will model that resonance as well. (Note: loudspeakers are usually used only at frequencies above their mechanical resonant ...
... At that resonant frequency, even small currents produce large motions of the voice coil, in turn producing large voltages—that is, the impedance at that frequency is large. We will model that resonance as well. (Note: loudspeakers are usually used only at frequencies above their mechanical resonant ...
One Question — three answers, based on the person asking…
... On average, over time, the power consumed by a theoretical inductor or capacitor is zero. In each power cycle, electrical current and power flows in both directions, loading and heating the wires and distribution circuits. An AC induction motor is equivalent to an inductor and a resistor in its simp ...
... On average, over time, the power consumed by a theoretical inductor or capacitor is zero. In each power cycle, electrical current and power flows in both directions, loading and heating the wires and distribution circuits. An AC induction motor is equivalent to an inductor and a resistor in its simp ...
D.J. Perreault, J. Hu, J.M. Rivas, Y. Han, O. Leitermann, R.C.N. Pilawa-Podgurski, A. Sagneri, and C.R. Sullivan, Opportunities and Challenges in Very High Frequency Power Conversion, 2009 IEEE Applied Power Electronics conference , Feb. 2009, pp. 1-14
... the values of α and β that provide a good fit to core-loss data vary as a function of frequency: α becomes larger at high frequency and β stays approximately constant or decreases [44]. Thus, at sufficiently high frequency, the improvements from scaling frequency cease and then reverse, so there is ...
... the values of α and β that provide a good fit to core-loss data vary as a function of frequency: α becomes larger at high frequency and β stays approximately constant or decreases [44]. Thus, at sufficiently high frequency, the improvements from scaling frequency cease and then reverse, so there is ...
10. energy efficient technologies in electrical systems
... decreases with speed for many VSD applications, the absolute loss is often not very significant. The power factor of a VSD drops drastically with speed, but at low power requirement the absolute kVAr requirement is low, so the loss is also generally not significant. In a suitable operating environme ...
... decreases with speed for many VSD applications, the absolute loss is often not very significant. The power factor of a VSD drops drastically with speed, but at low power requirement the absolute kVAr requirement is low, so the loss is also generally not significant. In a suitable operating environme ...
Power_Networks - University of British Columbia
... • The ionization characteristics of an insulating medium are determined by its intrinsic physio-chemical properties and its surrounding environmental context, that is, its specific usage for an electrical apparatus. • If the electrical field is sufficiently high the insulating medium goes through a ...
... • The ionization characteristics of an insulating medium are determined by its intrinsic physio-chemical properties and its surrounding environmental context, that is, its specific usage for an electrical apparatus. • If the electrical field is sufficiently high the insulating medium goes through a ...
Michelle Taylor, Ergon Energy
... against inadvertent or unauthorised tampering • Disconnection from the grid – when grid is disrupted, when frequency and voltage goes outside parameters and when DRM0 asserted – note this is required for all phases if any one phase has this requirement • Active anti-islanding shall operate within 2 ...
... against inadvertent or unauthorised tampering • Disconnection from the grid – when grid is disrupted, when frequency and voltage goes outside parameters and when DRM0 asserted – note this is required for all phases if any one phase has this requirement • Active anti-islanding shall operate within 2 ...
Utility frequency
The utility frequency, (power) line frequency (American English) or mains frequency (British English) is the frequency of the oscillations of alternating current (AC) in an electric power grid transmitted from a power plant to the end-user. In large parts of the world this is 50 Hz, although in the Americas and parts of Asia it is typically 60 Hz. Current usage by country or region is given in the list of mains power around the world.During the development of commercial electric power systems in the late 19th and early 20th centuries, many different frequencies (and voltages) had been used. Large investment in equipment at one frequency made standardization a slow process. However, as of the turn of the 21st century, places that now use the 50 Hz frequency tend to use 220–240 V, and those that now use 60 Hz tend to use 100–127 V. Both frequencies coexist today (Japan uses both) with no great technical reason to prefer one over the other and no apparent desire for complete worldwide standardization.Unless specified by the manufacturer to operate on both 50 and 60 Hz, appliances may not operate efficiently or even safely if used on anything other than the intended frequency.