The metal smelting and refining industry processes metal ores and scrap metal to obtain pure metals. The metal working industries process metals in order to.Switched- mode power supply - Wikipedia. Interior view of an ATXSMPS: below. A: input EMI filtering and bridge rectifier. B: input filter capacitors. Between B and C: primary side heat sink. C: transformer. Between C and D: secondary side heat sink. This data sheet provides an overview of the Cisco Nexus 5600 40G Platform Switches, including models and configurations, features and benefits, specifications. UPDATED "Combat Light" Soldier's Load Solution for the 21st century 1 st Tactical Studies Group (Airborne) Director Mike Sparks: after 28+ years of. D: output filter coil. E: output filter capacitors. Like other power supplies, an SMPS transfers power from a DC or AC source (often mains power) 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. Ideally, a switched- mode power supply dissipates no power. Voltage regulation is achieved by varying the ratio of on- to- off time. Gap Loss Coefficient Configuration Two-coil C core Single-coil C core Lamination Kj 0.0388 0.0775 0.1550 When designing inductors where there is a choice. Aptech Stock/Share prices, Aptech Live BSE/NSE, F&O Quote of Aptech with Historic price charts for NSE / BSE. Experts & Broker view on Aptech buy sell tips. Power supply manufacturer offering DC-DC converters, AC-DC power supplies, power modules, and military power solutions. UPDATED 12 September 2009 COMBAT PARACHUTE JUMP INTO PANAMA: THE SOLDIER'S LOAD AND SOLUTIONS. For a full-size copy of Jim Stovall's fabulous C-141B Starlifter print. Custom built ev motor for your electric car. Get an electric car motor from D&D Motor Systems. We have an electric vehicle motor for many light to medium duty. Learn about Zovirax (Acyclovir) may treat, uses, dosage, side effects, drug interactions, warnings, patient labeling, reviews, and related medications. INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY ENVIRONMENTAL HEALTH CRITERIA 207 ACETONE This report contains the collective views of an international. In contrast, a linear power supply regulates the output voltage by continually dissipating power in the pass transistor. This higher power conversion efficiency is an important advantage of a switched- mode power supply. Switched- mode power supplies may also be substantially smaller and lighter than a linear supply due to the smaller transformer size and weight. Switching regulators are used as replacements for linear regulators when higher efficiency, smaller size or lighter weight are required. They are, however, more complicated; their switching currents can cause electrical noise problems if not carefully suppressed, and simple designs may have a poor power factor. History. Kettering and his company Dayton Engineering Laboratories Company (Delco) goes into production for Cadillac. Variations of this ignition system were used in all non- diesel internal combustion engines until the 1. On 2. 3 June, British inventor Philip Ray Coursey applies for a patent in his country and United States, for his . Patent 3,0. 40,2. Joseph E. Murphy and Francis J. Starzec, from General Motors Company. One thing Holt has to his credit is that he created the switching power supply that allowed us to do a very lightweight computer. A linear regulator regulates either output voltage or current by dissipating the excess electric power in the form of heat, and hence its maximum power efficiency is voltage- out/voltage- in since the volt difference is wasted. In contrast, a switched- mode power supply regulates either output voltage or current by switching ideal storage elements, like inductors and capacitors, into and out of different electrical configurations. Ideal switching elements (e. This is because the inductor responds to changes in current by inducing its own voltage to counter the change in current, and this voltage adds to the source voltage while the switch is open. If a diode- and- capacitor combination is placed in parallel to the switch, the peak voltage can be stored in the capacitor, and the capacitor can be used as a DC source with an output voltage greater than the DC voltage driving the circuit. This boost converter acts like a step- up transformer for DC signals. A buck–boost converter works in a similar manner, but yields an output voltage which is opposite in polarity to the input voltage. Other buck circuits exist to boost the average output current with a reduction of voltage. In a SMPS, the output current flow depends on the input power signal, the storage elements and circuit topologies used, and also on the pattern used (e. The spectral density of these switching waveforms has energy concentrated at relatively high frequencies. As such, switching transients and ripple introduced onto the output waveforms can be filtered with a small LC filter. Advantages and disadvantages. Standby power loss is often much less than transformers. Disadvantages include greater complexity, the generation of high- amplitude, high- frequency energy that the low- pass filter must block to avoid electromagnetic interference (EMI), a ripple voltage at the switching frequency and the harmonic frequencies thereof. Very low cost SMPSs may couple electrical switching noise back onto the mains power line, causing interference with A/V equipment connected to the same phase. Non- power- factor- corrected SMPSs also cause harmonic distortion. SMPS and linear power supply comparison. The following table compares linear regulated and unregulated AC- to- DC supplies with switching regulators in general: Comparison of a linear power supply and a switched- mode power supply. Linear power supply. Switching power supply. Notes. Size and weight. Heatsinks for high power linear regulators add size and weight. Transformers, if used, are large due to low operating frequency (mains power frequency is at 5. Hz); otherwise can be compact due to low component count. Smaller transformer (if used; else inductor) due to higher operating frequency (typically 5. Hz – 1 MHz). Size and weight of adequate RF shielding may be significant. A transformer's power handling capacity of given size and weight increases with frequency provided that hysteresis losses can be kept down. Therefore, higher operating frequency means either a higher capacity or smaller transformer. Output voltage. With transformer used, any voltages available; if transformerless, limited to what can be achieved with a voltage doubler. If unregulated, voltage varies significantly with load. Any voltages available, limited only by transistor breakdown voltages in many circuits. Voltage varies little with load. A SMPS can usually cope with wider variation of input before the output voltage changes. Efficiency, heat, and powerdissipation. If regulated: efficiency largely depends on voltage difference between input and output; output voltage is regulated by dissipating excess power as heat resulting in a typical efficiency of 3. The only heat generated is in the non- ideal aspects of the components and quiescent current in the control circuitry. Switching losses in the transistors (especially in the short part of each cycle when the device is partially on), on- resistance of the switching transistors, equivalent series resistance in the inductor and capacitors, and core losses in the inductor, and rectifier voltage drop contribute to a typical efficiency of 6. However, by optimizing SMPS design (such as choosing the optimal switching frequency, avoiding saturation of inductors, and active rectification), the amount of power loss and heat can be minimized; a good design can have an efficiency of 9. Complexity. Unregulated may be simply a diode and capacitor; regulated has a voltage- regulating circuit and a noise- filtering capacitor; usually a simpler circuit (and simpler feedback loop stability criteria) than switched- mode circuits. Consists of a controller IC, one or several power transistors and diodes as well as a power transformer, inductors, and filter capacitors. Some design complexities present (reducing noise/interference; extra limitations on maximum ratings of transistors at high switching speeds) not found in linear regulator circuits. In switched- mode mains (AC- to- DC) supplies, multiple voltages can be generated by one transformer core, but that can introduce design/use complications: for example it may place minimum output current restrictions on one output. For this SMPSs have to use duty cycle control. One of the outputs has to be chosen to feed the voltage regulation feedback loop (usually 3. V or 5 V loads are more fussy about their supply voltages than the 1. V loads, so this drives the decision as to which feeds the feedback loop. The other outputs usually track the regulated one pretty well). Both need a careful selection of their transformers. Due to the high operating frequencies in SMPSs, the stray inductance and capacitance of the printed circuit board traces become important. Radio frequency interference. Mild high- frequency interference may be generated by AC rectifier diodes under heavy current loading, while most other supply types produce no high- frequency interference. Some mains hum induction into unshielded cables, problematical for low- signal audio. EMI/RFI produced due to the current being switched on and off sharply. Therefore, EMI filters and RF shielding are needed to reduce the disruptive interference. Long wires between the components may reduce the high frequency filter efficiency provided by the capacitors at the inlet and outlet. Stable switching frequency may be important. Electronic noise at the output terminals. Unregulated PSUs may have a little AC ripple superimposed upon the DC component at twice mains frequency (1. Hz). It can cause audible mains hum in audio equipment, brightness ripples or banded distortions in analog security cameras. Noisier due to the switching frequency of the SMPS. An unfiltered output may cause glitches in digital circuits or noise in audio circuits. This can be suppressed with capacitors and other filtering circuitry in the output stage. With a switched mode PSU the switching frequency can be chosen to keep the noise out of the circuits working frequency band (e. Electronic noise at the input terminals. Causes harmonic distortion to the input AC, but relatively little or no high frequency noise. Very low cost SMPS may couple electrical switching noise back onto the mains power line, causing interference with A/V equipment connected to the same phase. Non power- factor- corrected SMPSs also cause harmonic distortion. This can be prevented if a (properly earthed) EMI/RFI filter is connected between the input terminals and the bridge rectifier. Acoustic noise. Faint, usually inaudible mains hum, usually due to vibration of windings in the transformer or magnetostriction. Usually inaudible to most humans, unless they have a fan or are unloaded/malfunctioning, or use a switching frequency within the audio range, or the laminations of the coil vibrate at a subharmonic of the operating frequency.
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