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Gate Turn-off Thyristor
A gate turn-off thyristor (GTO) is a special type of thyristor, which is a high-power (.e.g. 1200V AC) semiconductor device. It was invented by General Electric. GTOs, as opposed to normal thyristors, are fully controllable switches which can be turned on and off by their gate lead. Device description Normal thyristors (silicon-controlled rectifiers) are not fully controllable switches (a "fully controllable switch" can be turned on and off at will). Thyristors can only be turned on using the gate lead, but cannot be turned off using the gate lead. Thyristors are switched on by a gate signal, but even after the gate signal is de-asserted (removed, reverse biased), the thyristor remains in the on state until a turn-off condition occurs (which can be the application of a reverse voltage to the terminals or a decrease of the forward current below a certain threshold value known as the "holding current"). Thus, a thyristor behaves like a normal semiconductor diode after it is turned ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Electric
General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energy, digital industry, additive manufacturing and venture capital and finance, but has since divested from several areas, now primarily consisting of the first four segments. In 2020, GE ranked among the Fortune 500 as the 33rd largest firm in the United States by gross revenue. In 2011, GE ranked among the Fortune 20 as the 14th most profitable company, but later very severely underperformed the market (by about 75%) as its profitability collapsed. Two employees of GE – Irving Langmuir (1932) and Ivar Giaever (1973) – have been awarded the Nobel Prize. On November 9, 2021, the company announced it would divide itself into three investment-grade public companies. On July 18, 2022, GE unveiled the brand names of the companies it will ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breakdown Voltage
The breakdown voltage of an insulator is the minimum voltage that causes a portion of an insulator to experience electrical breakdown and become electrically conductive. For diodes, the breakdown voltage is the minimum reverse voltage that makes the diode conduct appreciably in reverse. Some devices (such as TRIACs) also have a ''forward breakdown voltage''. Electrical breakdown Materials are often classified as conductors or insulators based on their resistivity. A conductor is a substance which contains many mobile charged particles called charge carriers which are free to move about inside the material. An electric field is created across a piece of the material by applying a voltage difference between electrical contacts on different sides of the material. The force of the field causes the charge carriers within the material to move, creating an electric current from the positive contact to the negative contact. For example, in metals one or more of the negatively cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescent Lamp
A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow. A fluorescent lamp converts electrical energy into useful light much more efficiently than an incandescent lamp. The typical luminous efficacy of fluorescent lighting systems is 50–100 lumens per watt, several times the efficacy of incandescent bulbs with comparable light output. For comparison, the luminous efficacy of an incandescent bulb may only be 16 lumens per watt. Fluorescent lamp fixtures are more costly than incandescent lamps because, among other things, they require a ballast to regulate current through the lamp, but the initial cost is offset by a much lower running cost. Compact fluorescent lamps are now available in the same popular sizes as incand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transistor
upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electrical power, power. The transistor is one of the basic building blocks of modern electronics. It is composed of semiconductor material, usually with at least three terminals for connection to an electronic circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Some transistors are packaged individually, but many more are found embedded in integrated circuits. Austro-Hungarian physicist Julius Edgar Lilienfeld proposed the concept of a field-effect transistor in 1926, but it was not possible to actually constru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insulated-gate Bipolar Transistor
An insulated-gate bipolar transistor (IGBT) is a three-terminal power semiconductor device primarily used as an electronic switch, which, as it was developed, came to combine high efficiency and fast switching. It consists of four alternating layers (P–N–P–N) that are controlled by a metal–oxide–semiconductor (MOS) gate structure. Although the structure of the IGBT is topologically the same as a thyristor with a "MOS" gate ( MOS-gate thyristor), the thyristor action is completely suppressed, and only the transistor action is permitted in the entire device operation range. It is used in switching power supplies in high-power applications: variable-frequency drives (VFDs), electric cars, trains, variable-speed refrigerators, lamp ballasts, arc-welding machines, induction hobs, and air conditioners. Since it is designed to turn on and off rapidly, the IGBT can synthesize complex waveforms with pulse-width modulation and low-pass filters, so it is also used in switching ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integrated Gate-commutated Thyristor
The integrated gate-commutated thyristor (IGCT) is a power semiconductor electronic device, used for switching electric current in industrial equipment. It is related to the gate turn-off (GTO) thyristor. It was jointly developed by Mitsubishi and ABB. Like the GTO thyristor, the IGCT is a fully controllable power switch, meaning that it can be turned both on and off by its control terminal (the gate). Gate drive electronics are integrated with the thyristor device.Eric Carroll, "IGCTs: Moving on the Right Track", ''Power Electronics Technology'', Aug 1, 200 retrieved on January 8, 2010. Device description An IGCT is a special type of thyristor. It is made of the integration of the gate unit with the Gate Commutated Thyristor (GCT) wafer device. The close integration of the gate unit with the wafer device ensures fast commutation of the conduction current from the cathode to the gate. The wafer device is similar to a gate turn-off thyristor (GTO). They can be turned on and off ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traction (engineering)
Traction, or tractive force, is the force used to generate motion between a body and a tangential surface, through the use of dry friction, though the use of shear force of the surface is also commonly used. Traction can also refer to the ''maximum'' tractive force between a body and a surface, as limited by available friction; when this is the case, traction is often expressed as the ratio of the maximum tractive force to the normal force and is termed the ''coefficient of traction'' (similar to coefficient of friction). It is the force which makes an object move over the surface by overcoming all the resisting forces like friction, normal loads(load acting on the tiers in negative 'Z' axis), air resistance, rolling resistance, etc. Definitions Traction can be defined as: In vehicle dynamics, tractive force is closely related to the terms tractive effort and drawbar pull, though all three terms have different definitions. Coefficient of traction The ''coefficient of traction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saturable Reactor
A saturable reactor in electrical engineering is a special form of inductor where the magnetic core can be deliberately saturated by a direct electric current in a control winding. Once saturated, the inductance of the saturable reactor drops dramatically. This decreases inductive reactance and allows increased flow of the alternating current (AC). Design considerations Saturable reactors provide a very simple means to remotely and proportionally control the AC through a load such as an incandescent lamp; the AC current is roughly proportional to the direct current (DC) through the control winding. The power windings, the control winding, and the core are arranged so that the control winding is well isolated from the AC power. The AC power windings are also usually configured so that they self-cancel any AC voltage that might otherwise be induced in the control winding. Because the required inductance to achieve dimming varies with the size of the load, saturable reactors often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snubber
A snubber is a device used to suppress ("snub") a phenomenon such as voltage transients in electrical systems, pressure transients in fluid systems (caused by for example water hammer) or excess force or rapid movement in mechanical systems. Electrical systems Snubbers are frequently used in electrical systems with an inductive load where the sudden interruption of current flow leads to a large counter-electromotive force: a rise in voltage across the current switching device that opposes the change in current, in accordance with Faraday's law. This transient can be a source of electromagnetic interference (EMI) in other circuits. Additionally, if the voltage generated across the device is beyond what the device is intended to tolerate, it may damage or destroy it. The snubber provides a short-term alternative current path around the current switching device so that the inductive element may be safely discharged. Inductive elements are often unintentional, arising from the curr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insulated Gate Bipolar Transistor
An insulated-gate bipolar transistor (IGBT) is a three-terminal power semiconductor device primarily used as an electronic switch, which, as it was developed, came to combine high efficiency and fast switching. It consists of four alternating layers (P–N–P–N) that are controlled by a metal–oxide–semiconductor (MOS) Metal gate, gate structure. Although the structure of the IGBT is topologically the same as a thyristor with a "MOS" gate (MOS-controlled thyristor, MOS-gate thyristor), the thyristor action is completely suppressed, and only the transistor action is permitted in the entire device operation range. It is used in switching power supply, switching power supplies in high-power applications: variable-frequency drives (VFDs), electric cars, trains, variable-speed refrigerators, lamp ballasts, arc-welding machines, induction hobs, and air conditioners. Since it is designed to turn on and off rapidly, the IGBT can synthesize complex waveforms with pulse-width modulat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Switched-mode Power Supply
A switched-mode power supply (switching-mode power supply, switch-mode power supply, switched power supply, SMPS, or switcher) is an electronic power supply that incorporates a switching regulator to convert electrical power efficiently. Like other power supplies, an SMPS transfers power from a DC or AC source (often mains power, see AC adapter) to DC loads, such as a personal computer, while converting voltage and current characteristics. Unlike a linear power supply, the pass transistor of a switching-mode supply continually switches between low-dissipation, full-on and full-off states, and spends very little time in the high dissipation transitions, which minimizes wasted energy. A hypothetical ideal switched-mode power supply dissipates no power. Voltage regulation is achieved by varying the ratio of on-to-off time (also known as duty cycles). In contrast, a linear power supply regulates the output voltage by continually dissipating power in the pass transistor. The switche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the interval of time between events, so the period is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times a minute (2 hertz), the period, —the interval at which the beats repeat—is half a second (60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. Definitions and units For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term ''frequency'' is defined as the number of cycles or vibrations per unit of time. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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