|
Active EMI Reduction
In the field of EMC, active EMI reduction (or active EMI filtering) refers to techniques aimed to reduce or to filter electromagnetic noise (EMI) making use of active electronic components. Active EMI reduction contrasts with ''passive'' filtering techniques, such as RC filters, LC filters RLC filters, which includes only passive electrical components. Hybrid solutions including both active and passive elements exist. Standards concerning conducted and radiated emissions published by IEC and FCC set the maximum noise level allowed for different classes of electrical devices. The frequency range of interest spans from 150 kHz to 30 MHz for conducted emissions and from 30 MHz to 40 GHz for radiated emissions. Meeting these requirements and guaranteeing the functionality of an electrical apparatus subject to electromagnetic interference are the main reason to include an EMI filter. In an electrical system, power converters, i.e. DC/DC converters, inverters a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Compatibility
Electromagnetic compatibility (EMC) is the ability of electrical equipment and systems to function acceptably in their electromagnetic environment, by limiting the unintentional generation, propagation and reception of electromagnetic energy which may cause unwanted effects such as electromagnetic interference (EMI) or even physical damage in operational equipment. The goal of EMC is the correct operation of different equipment in a common electromagnetic environment. It is also the name given to the associated branch of electrical engineering. EMC pursues three main classes of issue. Emission is the generation of electromagnetic energy, whether deliberate or accidental, by some source and its release into the environment. EMC studies the unwanted emissions and the countermeasures which may be taken in order to reduce unwanted emissions. The second class, susceptibility, is the tendency of electrical equipment, referred to as the victim, to malfunction or break down in the presen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operational Amplifier
An operational amplifier (often op amp or opamp) is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op amp produces an output potential (relative to circuit ground) that is typically 100,000 times larger than the potential difference between its input terminals. The operational amplifier traces its origin and name to analog computers, where they were used to perform mathematical operations in linear, non-linear, and frequency-dependent circuits. The popularity of the op amp as a building block in analog circuits is due to its versatility. By using negative feedback, the characteristics of an op-amp circuit, its gain, input and output impedance, bandwidth etc. are determined by external components and have little dependence on temperature coefficients or engineering tolerance in the op amp itself. Op amps are used widely in electronic devices today, including a vast array of consumer, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kirchhoff's Circuit Laws
Kirchhoff's circuit laws are two equalities that deal with the current and potential difference (commonly known as voltage) in the lumped element model of electrical circuits. They were first described in 1845 by German physicist Gustav Kirchhoff. This generalized the work of Georg Ohm and preceded the work of James Clerk Maxwell. Widely used in electrical engineering, they are also called Kirchhoff's rules or simply Kirchhoff's laws. These laws can be applied in time and frequency domains and form the basis for network analysis. Both of Kirchhoff's laws can be understood as corollaries of Maxwell's equations in the low-frequency limit. They are accurate for DC circuits, and for AC circuits at frequencies where the wavelengths of electromagnetic radiation are very large compared to the circuits. Kirchhoff's current law This law, also called Kirchhoff's first law, or Kirchhoff's junction rule, states that, for any node (junction) in an electrical circuit, the sum of currents ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norator
In electronics, a norator is a theoretical linear, time-invariant one-port which can have an arbitrary current and voltage between its terminals. A norator represents a controlled voltage or current source with infinite gain. {{cite book , author=Verhoeven C J M van Staveren A Monna G L E Kouwenhoven M H L & Yildiz E , title=Structured electronic design: negative feedback amplifiers , year= 2003 , publisher=Kluwer Academic , location=Boston/Dordrecht/London , isbn=1-4020-7590-1 , pages=§2.2.1.1 pp. 30–32 , url=https://books.google.com/books?id=p8wDptzCMrUC&pg=PA24 Inserting a norator in a circuit schematic provides whatever current and voltage the outside circuit demands, in particular, the demands of Kirchhoff's circuit laws. For example, the output of an ideal opamp behaves as a norator, producing nonzero output voltage and current that meet circuit requirements despite a zero input. A norator is often paired with a nullator to form a nullor A nullor is a theoretical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nullator
In electronics, a nullator is a theoretical linear, time-invariant one-port ''defined'' as having zero current and voltage across its terminals. Nullators are strange in the sense that they simultaneously have properties of both a short (zero voltage) and an open circuit (zero current). They are neither current nor voltage sources, yet both at the same time. {{cite book , author=Verhoeven C J M van Staveren A Monna G L E Kouwenhoven M H L & Yildiz E , title=Structured electronic design: negative feedback amplifiers , year= 2003 , publisher=Kluwer Academic , location=Boston/Dordrecht/London , isbn=1-4020-7590-1 , pages=§2.2.1.1 pp. 30–32 , url=https://books.google.com/books?id=p8wDptzCMrUC&pg=PA24 Inserting a nullator in a circuit schematic imposes a ''mathematical constraint'' on how that circuit must behave, forcing the circuit itself to adopt whatever arrangements needed to meet the condition. For example, the inputs of an ideal operational amplifier (with negative feedback) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norton's Theorem
In direct-current circuit theory, Norton's theorem, also called the Mayer–Norton theorem, is a simplification that can be applied to networks made of linear time-invariant resistances, voltage sources, and current sources. At a pair of terminals of the network, it can be replaced by a current source and a single resistor in parallel. For alternating current (AC) systems the theorem can be applied to reactive impedances as well as resistances. The Norton equivalent circuit is used to represent any network of linear sources and impedances at a given frequency. Norton's theorem and its dual, Thévenin's theorem, are widely used for circuit analysis simplification and to study circuit's initial-condition and steady-state response. Norton's theorem was independently derived in 1926 by Siemens & Halske researcher Hans Ferdinand Mayer (1895–1980) and Bell Labs engineer Edward Lawry Norton (1898–1983). To find the equivalent, the Norton current ''I''no is calculated as th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Noise Circuit
Simple or SIMPLE may refer to: * Simplicity, the state or quality of being simple Arts and entertainment * ''Simple'' (album), by Andy Yorke, 2008, and its title track * "Simple" (Florida Georgia Line song), 2018 * "Simple", a song by Johnny Mathis from the 1984 album ''A Special Part of Me'' * "Simple", a song by Collective Soul from the 1995 album '' Collective Soul'' * "Simple", a song by Katy Perry from the 2005 soundtrack to '' The Sisterhood of the Traveling Pants'' * "Simple", a song by Khalil from the 2017 album '' Prove It All'' * "Simple", a song by Kreesha Turner from the 2008 album '' Passion'' * "Simple", a song by Ty Dolla Sign from the 2017 album ''Beach House 3'' deluxe version * ''Simple'' (video game series), budget-priced console games Businesses and organisations * Simple (bank), an American direct bank * SIMPLE Group, a consulting conglomeration based in Gibraltar * Simple Shoes, an American footwear brand * Simple Skincare, a British brand of so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feed Forward (control)
A feed forward (sometimes written feedforward) is an element or pathway within a control system that passes a controlling signal from a source in its external environment to a load elsewhere in its external environment. This is often a command signal from an external operator. A control system which has only feed-forward behavior responds to its control signal in a pre-defined way without responding to the way the load reacts; it is in contrast with a system that also has feedback, which adjusts the input to take account of how it affects the load, and how the load itself may vary unpredictably; the load is considered to belong to the external environment of the system. In a feed-forward system, the control variable adjustment is not error-based. Instead it is based on knowledge about the process in the form of a mathematical model of the process and knowledge about, or measurements of, the process disturbances. Some prerequisites are needed for control scheme to be reliable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feedback
Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handled carefully when applied to feedback systems: History Self-regulating mechanisms have existed since antiquity, and the idea of feedback had started to enter economic theory in Britain by the 18th century, but it was not at that time recognized as a universal abstraction and so did not have a name. The first ever known artificial feedback device was a float valve, for maintaining water at a constant level, invented in 270 BC in Alexandria, Egypt. This device illustrated the principle of feedback: a low water level opens the valve, the rising water then provides feedback into the system, closing the valve when the required level is reached. This then reoccurs in a circular fashion as the water level fluctuates. Centrifugal governors were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Mode
Differential signalling is a method for electrically transmitting information using two complementary signals. The technique sends the same electrical signal as a differential pair of signals, each in its own conductor. The pair of conductors can be wires in a twisted-pair or ribbon cable or traces on a printed circuit board. Electrically, the two conductors carry voltage signals which are equal in magnitude, but of opposite polarity. The receiving circuit responds to the difference between the two signals, which results in a signal with a magnitude twice as large. The symmetrical signals of differential signalling may be referred to as ''balanced'', but this term is more appropriately applied to balanced circuits and balanced lines which reject common-mode interference when fed into a differential receiver. Differential signalling does not make a line balanced, nor does noise rejection in balanced circuits require differential signalling. Differential signalling is to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common-mode Signal
Common-mode signal is the voltage common to both input terminals of an electrical device. In telecommunication, the common-mode signal on a transmission line is also known as longitudinal voltage. In most electrical circuits the signal is transferred by a differential voltage between two conductors. If the voltages on these conductors are U1 and U2, the common-mode signal is the half-sum of the voltages: :U_\text = \frac When referenced to the local common or ground, a common-mode signal appears on both lines of a two-wire cable, in phase and with equal amplitudes. Technically, a common-mode voltage is one-half the vector sum of the voltages from each conductor of a balanced circuit to local ground or common. Such signals can arise from one or more of the following sources: * Radiated signals coupled equally to both lines, * An offset from signal common created in the driver circuit, or * A ground differential between the transmitting and receiving locations. Noise induced into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Current
Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. The electric current flows in a constant direction, distinguishing it from alternating current (AC). A term formerly used for this type of current was galvanic current. The abbreviations ''AC'' and ''DC'' are often used to mean simply ''alternating'' and ''direct'', as when they modify ''current'' or ''voltage''. Direct current may be converted from an alternating current supply by use of a rectifier, which contains electronic elements (usually) or electromechanical elements (historically) that allow current to flow only in one direction. Direct current may be converted into alternating current via an inverter. Direct current has many uses, from the charging of batteries to large power sup ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
