Harmonic distortion problems include equipment overheating, motor failures, capacitor failure and inaccurate power metering. The topic of power system harmonics was covered for the first time 20 years ago and the first edition has become a standard reference work in this area. Unprecedented developments in power electronic devices and their integration at all levels in the power system require a new look at the causes and effects of these problems, and the state of hardware and software available for harmonic assessment.
1.1 The balance of charges on conductors:
In conductors there are charged particles which can be freely
move under any small force. Therefore the balance of charges on
conductors can be observed under these circumstances:
The electric field equals zero everywhere inside the conductor
E = 0
The electric potential is constant inside the conductor
V = const
The electric field vector on the surface of conductors direct along the
normal of the surface at each point
E = En
The surface of conductors is equipotential
Inside conductors there is no charge.
Energy harvesting from ambient waste energy for the purpose of running low-powered electronics
has emerged during the last decade as an enabling technology for wireless applications.
The goal of this technology is to provide remote sources of electric power and/or to recharge
storage devices, such as batteries and capacitors. The concept has ecological ramifications in
reducing the chemical waste produced by replacing batteries and potential monetary gains by
reducing maintenance costs.
Double-layer carbon supercapacitors (electrochemical double-layer capacitor (EDLCs)) based on two carbon electrodes of high surface area separated by an electrolyte are the most popular electrochemical supercapacitors. The charge process is electrostatic with charge separation at the two electrode–electrolyte interfaces. The EDLCs can thus be modeled with two capacitances in series with what is called equivalent series resistance (ESR).
The origin of the electrolytic capacitor or condenser can be traced
to the second half of the 19th century when the discovery was made
(Wheatstone, Buff, Ducretet) that a film can be formed on aluminum
electrochemically and that it will exhibit unidirectional electrical conductance
and other peculiar properties. One of the early attempted
applications of the electrolytic capacitor was in conjunction with the
starting of single-phase induction motors; efforts were also made to
utilize it for power factor correction in alternating current circuits.
Electrochemical double-layer capacitors store electrical energy at the phase boundary between an electronic conductor (electrode) and a liquid ionic conductor (electrolyte solution). In contrast to that, electrostatic space charge layers at dielectric oxide ﬁlms, formed anodically on etched aluminum or tantalum foils of conventional electrolytic capacitors, should not be confused with the electrochemical double layer.
Conventional electrostatic capacitors contain a dielectric instead of an electrolyte solution. Electrochemical supercapacitors, however, contain a liquid electrolyte (aqueous, nonaqueous), and can be classiﬁed by the electrode material used (carbon, metal oxide, polymer) and the operating principle (double-layer capacitance, redox pseudocapacitance, hybrid capacitance).
Tuyển tập các báo cáo nghiên cứu khoa học trên tạp chí khoa học vật lý quốc tế đề tài: Synthesis and Characterization of Bismuth Tantalate Binary Materials for Potential Application in Multilayer Ceramic Capacitors (MLCC)
One way to solve the single phase problem is to build a 2-phase motor, deriving 2-phase power from single phase. This requires a motor with two windings spaced apart 90o electrical, fed with two phases of current displaced 90o in time. This is called a permanent-split capacitor motor in Figure
Capacitors store electrical charge. Generally, that charge is stored physically, as equal quantities of positive and negative charge are separated on opposite faces of an insulating material. When the two faces are connected by an external current path, current ﬂows until complete charge balance is achieved. The capacitor can then be returned to its charged state by applying voltage.
Tuyển tập các báo cáo nghiên cứu khoa học ngành toán học được đăng trên tạp chí toán học quốc tế đề tài: Characterization of epitaxial GaAs MOS capacitors using atomic layer-deposited TiO2/Al2O3 gate stack: study of Ge auto-doping and p-type Zn doping
Resistors in an AC circuit, capacitors in an AC circuit, inductors in an AC circuit, the RLC series circuit, power in an ac circuit, resonance in a series rlc circuit, the transformer,... As the main contents of the document "Alternating current circuits and electromagnetic waves". Invite you to consult.
Bài giảng Tiếng Anh chuyên ngành Viễn thông - Unit 2 (part 1): Component values. The following will be discussed in this chapter: Resistor values, capacitor values, diode codes, linking facts and ideas.
Multilayer ceramic capacitors (MLCC) are indispensable electronic components for
advanced electronic technology2-12, but larger capacity and smaller size are needed for
future electronic devices. To meet these needs, BaTiO3 particles were downsized, but
ferroelectric ceramics lose their ferroelectricity when their particle size is decreased and lose
ferroelectricity entirely at a critical size2-11. This is known as the size effect and it impedes the
progress of MLCC, so a novel solution has been eagerly anticipated....
Electronics may be defined as the science and technology of
electronic devices and systems.Electronic devices are primarily non-linear devices such as
diodes and transistors and in general integrated circuits (ICs) in
which small signals (voltages and currents) are applied to them.
Of course, electronic systems may include resistors, capacitors
and inductors as well.
Equivalent circuit device models are critical for the accurate design and modelling of RF components including transistors, diodes, resistors, capacitors and inductors. This chapter will begin with the bipolar transistor starting with the basic T and then the π model at low frequencies and then show how this can be extended for use at high frequencies. These models should be as simple as possible to enable a clear understanding of the operation of the circuit and allow easy analysis. They should then be extendible to include the parasitic components to enable accurate optimisation....
- AT90S2313: Vào Library/Pick (nhấn “p”): Catagory/Microprocessor ICs/AVR
familly/AT90S2313. Bạn có thể chọn lk bằng việc gõ AT90S2313 vào Keywords.
- Tụ: Nhấn “p”,trong Keywords đánh Capacitor;trong Sub-Catagory/Generic/Cap.
đổi giá trị của tụ thành 33pF.
- Nhấn “p”/Keywords=7seg, Catagory/Optoelectronic/7 seg C-C.
- Keywords=Crystal, để lấy thạch anh, thay đổi giá trị =1MHz.
Acicular BaTiO3 particles were developed using solution systems. The morphology of BaC2O4
0.5H2O was controlled to acicular shape. Its phase transition to BaTiO3 was realized by
introducing Ti ions from the coprecipitated amorphous phase. Acicular BaTiO3 particles have
an aspect ratio as high as 18 and the particle size can be controlled by varying the growth
period of BaC2O4 · 0.5H2O which governs the size of BaC2O4 · 0.5H2O particles. Acicular
particles of crystalline BaTiO3 can be used for ultra-thin multilayer ceramic capacitors. ...
Bài báo trình bày ảnh hưởng của tụ bù dọc 500kV đến ổn định điện áp của hệ thống điện Việt Nam và giải pháp ứng dụng thiết bị bù dọc điều khiển bằng thyristor TCSC (ThyristorControlled Series Capacitor) để nâng cao hiệu quả vận hành. Các kết quả phân tích được thực hiện cho 1 số ngày đặc trưng trong các năm 2005-2006.