what is the meaning of ac dc current
Alternating current direct current
Alternating current Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, fans and electric lamps into a wall socket. A common source of DC power is a battery cell in a flashlight. The abbreviations "AC" and "DC" are often used to mean simply "alternating" and "direct", as when they modify "current" or "voltage".
Alternating current
formed and played bass in the London-based band Grapefruit—initially called "The Grapefruit"—with three former members of Tony Rivers and the Castaways, John Perry, Geoff Swettenham, and Pete Swettenham. Malcolm and Angus Young developed the idea for the band's name after their sister, Margaret Young, saw the initials "AC/DC" on a sewing machine. "AC/DC" is an abbreviation meaning "alternating current/direct current" electricity. The brothers felt that this name symbolised the band's raw energy, power-driven performances of their music. "AC/DC" is pronounced one letter at a time, though the band are colloquially known as "Acca Dacca" in Australia. The AC/DC band name
AC/DC
Pulsed DC Pulsed DC (PDC) or pulsating direct current is a periodic current which changes in value but never changes direction. Some authors use the term pulsed DC to describe a signal consisting of one or more rectangular ("flat-topped"), rather than sinusoidal, pulses. Pulsed DC is commonly produced from AC (alternating current) by a half-wave rectifier or a full-wave rectifier. Full wave rectified ac is more commonly known as Rectified AC. PDC has some characteristics of both alternating current (AC) and direct current (DC) waveforms. The voltage of a DC wave is roughly constant, whereas the voltage of an AC
Pulsed DC
AC/DC receiver design An AC/DC receiver design is a style of power supply of vacuum tube radio or television receivers that eliminated the bulky and expensive mains transformer. A side-effect of the design was that the receiver could in principle operate from a DC supply as well as an AC supply. Consequently, they were known as "AC/DC receivers". In the early days of radio, mains electricity was supplied at different voltages in different places, and either direct current (DC) or alternating current (AC) was supplied. There are three ways of powering electronic equipment. AC-only equipment would rely on a transformer
AC/DC receiver design
combined AC and DC transmission system was estimated to save consumers in Los Angeles approximately US $600,000 per day by use of cheaper electric power from dams on the Columbia River. One advantage of direct current over AC is that DC current penetrates the entire conductor as opposed to AC current which only penetrates to the skin depth. For the same conductor size the effective resistance is greater with AC than DC, hence more power is lost as heat. In general the total costs for HVDC are less than an AC line if the line length is over 500–600 miles,
Pacific DC Intertie
DC bias When describing a periodic function in the time domain, the DC bias, DC component, DC offset, or DC coefficient is the mean amplitude of the waveform. If the mean amplitude is zero, there is no DC bias. A waveform with no DC bias is known as a "DC balanced" or "DC free" waveform. The term originates in electronics, where "DC" refers to a direct current voltage. In contrast, various other non-DC frequencies are analogous to superimposed alternating current (AC) voltages or currents, hence called "AC components" or "AC coefficients". In the design of electronic amplifier circuits, every active
DC bias
of engine speed. Energy is lost during the process of converting the electrical energy to mechanical energy. Approximately 90% of the energy from the battery is converted to mechanical energy, the losses being in the motor and drivetrain. Usually, direct current (DC) electricity is fed into a DC/AC inverter where it is converted to alternating current (AC) electricity and this AC electricity is connected to a 3-phase AC motor. For electric trains, forklift trucks, and some electric cars, DC motors are often used. In some cases, universal motors are used, and then AC or DC may be employed. In recent
Electric vehicle
frequency. Power conversion systems often incorporate redundancy and voltage regulation. One way of classifying power conversion systems is according to whether the input and output are alternating current (AC) or direct current (DC). The following devices can convert DC to DC: The following devices can convert DC to AC: The following devices can convert AC to DC: The following devices can convert AC to AC: There are also devices and methods to convert between power systems designed for single and three-phase operation. The standard power voltage and frequency varies from country to country and sometimes within a country. In North
Electric power conversion
Z-source inverter A Z-source inverter is a type of power inverter, a circuit that converts direct current to alternating current. It functions as a buck-boost inverter without making use of DC-DC converter bridge due to its unique circuit topology. Impedance (Z-) Source networks provide an efficient means of power conversion between source and load in a wide range of electric power conversion applications (dc–dc, dc–ac, ac–dc, ac– ac) [3], [4]. Z-source-related research has grown rapidly since it was first proposed in 2002 by Prof. F. Z. Peng. A comprehensive pulse width modulation scheme for Z-source inverters was proposed by Prof.
Z-source inverter
Polarity symbols Polarity symbols are a notation found on electrical devices that use direct current (DC) power, when this is or may be provided from an alternating current (AC) source via an AC adapter. The adapter typically supplies power to the device through a thin electrical cord which terminates in a coaxial power connector often referred to as a "barrel plug" (so-named because of its cylindrical shape). The polarity of the adapter cord and plug must match the polarity of the device, meaning that the positive contact of the plug must mate with the positive contact in the receptacle, and
Polarity symbols
(−), meaning negative. The symbol connected to the dot (usually the symbol found to the right) denotes the polarity of the center/tip, whereas the symbol connected to the broken circle denotes the polarity of the barrel/ring. When a device or adapter is described simply as having "positive polarity" or "negative polarity", this denotes the polarity of the center/tip. Polarity symbols Polarity symbols are a notation found on electrical devices that use direct current (DC) power, when this is or may be provided from an alternating current (AC) source via an AC adapter. The adapter typically supplies power to the device
Polarity symbols
Alternating current Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, fans and electric lamps into a wall socket. A common source of DC power is a battery cell in a flashlight. The abbreviations "AC" and "DC" are often used to mean simply "alternating" and "direct", as when they modify "current" or "voltage".
Alternating current
Direct current Direct current (DC) is the unidirectional flow of electric charge. A battery is a good example of a DC power supply. Direct current may flow in 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
Direct current
of force are perpendicular to the direction of the electric current, which may be either alternating current (AC) or some form of direct current (DC) (rectified AC). The presence of a surface or subsurface discontinuity in the material allows the magnetic flux to leak, since air cannot support as much magnetic field per unit volume as metals. To identify a leak, ferrous particles, either dry or in a wet suspension, are applied to a part. These are attracted to an area of flux leakage and form what is known as an indication, which is evaluated to determine its nature, cause,
Magnetic particle inspection
used to balance the DC neutral wire. Rotary converter A rotary converter is a type of electrical machine which acts as a mechanical rectifier, inverter or frequency converter. Rotary converters were used to convert alternating current (AC) to direct current (DC), or DC to AC power, before the advent of chemical or solid state power rectification and inverting. They were commonly used to provide DC power for commercial, industrial and railway electrification from an AC power source. Rotary converters are still used as frequency converters. The rotary converter can be thought of as a motor-generator, where the two machines share
Rotary converter
to provide the voltages for heater and plate circuits. AC/DC equipment would connect all the tube heaters in series to match the supply voltage; a rectifier would convert AC to the direct current required for operation. When connected to a DC supply, the rectifier stage of the power supply performed no active function. DC-only equipment would only run from a DC supply and included no rectifier stage. DC is almost never used in mains power distribution anymore. Different radio set models were required for AC, DC mains, and battery operation. For example, a 1933 Murphy radio with essentially the same
AC/DC receiver design
polyphase winding is used and the pole-pieces of the rotor are shaped (claw-pole). Automotive alternators are usually belt-driven at 5-10 times crankshaft speed. The alternator runs at various RPM (which varies the frequency) since it is driven by the engine. This is not a problem because the alternating current is rectified to direct current. Despite their names, both 'DC generators' (or 'dynamos') and 'alternators' initially produce alternating current. In a so-called 'DC generator', this AC current is generated in the rotating armature, and then converted to DC by the commutator and brushes. In an 'alternator', the AC current is generated
Alternator (automotive)
cannot be used, similarly if 50 Hz AC electrification is used then 50 Hz AC track circuits cannot be used. To accommodate this, AC track circuits use alternating current signals instead of direct current (DC) but typically, the AC frequency is in the range of audio frequencies, from 91 Hz up to 10 kHz. The relays are arranged to detect the selected frequency and to ignore DC and AC traction frequency signals. Again, failsafe principles dictate that the relay interprets the presence of the signal as unoccupied track, whereas a lack of a signal indicates the presence of a train.
Track circuit
Rotary converter A rotary converter is a type of electrical machine which acts as a mechanical rectifier, inverter or frequency converter. Rotary converters were used to convert alternating current (AC) to direct current (DC), or DC to AC power, before the advent of chemical or solid state power rectification and inverting. They were commonly used to provide DC power for commercial, industrial and railway electrification from an AC power source. Rotary converters are still used as frequency converters. The rotary converter can be thought of as a motor-generator, where the two machines share a single rotating armature and set of
Rotary converter
to convert one type of electric current into another, for example DC into AC. They were multi-field single-rotor devices with two or more sets of rotating contacts (either commutators or sliprings, as required), one to provide power to one set of armature windings to turn the device, and one or more attached to other windings to produce the output current. The rotary converter can directly convert, internally, any type of electric power into any other. This includes converting between direct current (DC) and alternating current (AC), three phase and single phase power, 25 Hz AC and 60 Hz AC, or
Dynamo
BIPV modules produce direct current power from range 10 watts to 100 watts. Integrated circuit-based AC nanoinverter on each module increases harvest rate by 30% and substantially decreases the installation constraints. DC nanoconverter-on-chip is capable to harvest from microwatts power and as low as 80mV (0.08V) voltage. Harvest rate improves 30%-70% with integrated MPPT and DC-DC booster Nanoinverter A nanoinverter, also referred as nano inverter or solar nano inverter, converts direct current (DC) from a single solar cell or small solar panel to alternating current (AC). Nanoinverters contrast with microinverter devices, which are connected to larger than 100 Watt solar
Nanoinverter
Regulated power supply A regulated power supply is an embedded circuit; it converts unregulated AC (Alternating Current)into a constant DC. With the help of a rectifier it converts AC supply into DC. Its function is to supply a stable voltage (or less often current), to a circuit or device that must be operated within certain power supply limits. The output from the regulated power supply may be alternating or unidirectional, but is nearly always DC (Direct Current). The type of stabilization used may be restricted to ensuring that the output remains within certain limits under various load conditions, or it
Regulated power supply
much greater power loss than low-current, high-voltage ones. This holds whether DC or AC is used. Converting DC power from one voltage to another required a large spinning rotary converter or motor-generator set, which was difficult, expensive, inefficient, and required maintenance, whereas with AC the voltage can be changed with simple and efficient transformers that have no moving parts and require very little maintenance. This was the key to the success of the AC system. Modern transmission grids regularly use AC voltages up to 765,000 volts. Power electronic devices such as the mercury-arc valve and thyristor made high-voltage direct current
War of the currents
alternating current (AC) systems, the movement of electric charge periodically reverses direction. AC is the form of electric power most commonly delivered to businesses and residences. The usual waveform of an AC power circuit is a sine wave. Certain applications use different waveforms, such as triangular or square waves. Audio and radio signals carried on electrical wires are also examples of alternating current. An important goal in these applications is recovery of information encoded (or "modulated") onto the AC signal. In contrast, direct current (DC) is the unidirectional flow of electric charge, or a system in which the movement of
Electric current
Electric Corporation". The Westinghouse company installed 30 more AC-lighting systems within a year and by the end of 1887 it had 68 alternating current power stations to Edison's 121 DC-based stations. This competition with Edison led in the late 1880s to what has been called the "War of Currents" with Thomas Edison and his company joining in with a spreading public perception that the high voltages used in AC distribution were unsafe. Edison even suggested a Westinghouse AC generator be used in the State of New York's new electric chair. Westinghouse also had to deal with an AC rival, the
George Westinghouse
connectors). The new USB-C plug is expected to eventually become the new standard for charging (and data transfer) over USB. DC connector A DC connector (or DC plug, for one common type of connector) is an electrical connector for supplying direct current (DC) power. Compared to domestic AC power plugs and sockets, DC connectors have many more standard types that are not interchangeable. The dimensions and arrangement of DC connectors can be chosen to prevent accidental interconnection of incompatible sources and loads. Types vary from small coaxial connectors used to power portable electronic devices from AC adapters, to connectors used
DC connector
that should be used and the New York Medico-Legal Society, an informal society composed of doctors and lawyers, was given the task of determining these factors. In September 1888, a committee was formed and recommended 3000 volts, although the type of electricity, direct current (DC) or alternating current (AC), was not determined, and since tests up to that point had been done on animals smaller than a human (dogs), some members were unsure that the lethality of AC had been conclusively proven. At this point the state's efforts to design the electric chair became intermixed with what has become to
Electric chair
Choke (electronics) In electronics, a choke coil is an inductor used to block higher-frequency while passing lower-frequency of direct current (DC) or alternating current (AC) in an electrical circuit, A choke usually consists of a coil of insulated wire often wound on a magnetic core, although some consist of a doughnut-shaped "bead" of ferrite material strung on a wire. The choke's impedance increases with frequency. Its low electrical resistance passes both AC and DC with little power loss, but its reactance limits the amount of AC passed. The name comes from blocking—"choking"—high frequencies while passing low frequencies. It is a
Choke (electronics)
alternating current into either DC for vehicle applications or AC 50/60 Hz for power generation application. The power electronics architecture can have different configurations but may consist of a rectifier, a converter, and an inverter stage. The rectifier transforms the unregulated AC into a DC power. As the turbogenerator output voltage depends on speed and load, the rectified voltage is subsequently regulated to a fixed voltage by a converter stage. For AC applications the inverter transforms DC to AC and synchronizes it with the electricity grid. A contactor connects or disconnects the inverter output to the grid depending on whether
Electric turbo compound
on electrical streetcars, were restricted in use to being only a few miles from the DC generators. DC power, despite its restrictions, had become very useful. A rotary converter, a type of motor generator, was used to convert alternating current (AC) to direct current (DC) for railway electrification from an AC power source. Factories were also heavy power users. Transforming AC voltages up to high voltages for long distance transmission and down to lower voltages at locations close to their use was a very attractive way to get access to a new source of power. Improvements in transformer design allowed
Folsom Powerhouse State Historic Park
as for traditional (radio or microwave) rectennas. Incident light on the antenna causes electrons in the antenna to move back and forth at the same frequency as the incoming light. This is caused by the oscillating electric field of the incoming electromagnetic wave. The movement of electrons is an alternating current (AC) in the antenna circuit. To convert this into direct current (DC), the AC must be rectified, which is typically done with a diode. The resulting DC current can then be used to power an external load. The resonant frequency of antennas (frequency which results in lowest impedance and
Optical rectenna
DC connector A DC connector (or DC plug, for one common type of connector) is an electrical connector for supplying direct current (DC) power. Compared to domestic AC power plugs and sockets, DC connectors have many more standard types that are not interchangeable. The dimensions and arrangement of DC connectors can be chosen to prevent accidental interconnection of incompatible sources and loads. Types vary from small coaxial connectors used to power portable electronic devices from AC adapters, to connectors used for automotive accessories and for battery packs in portable equipment. Small cylindrical connectors come in a variety of sizes. They
DC connector
fifth executive member. Three of these companies have developed electric vehicles that use TEPCO's DC connector for quick charging. Most electric vehicles (EVs) have an on-board charger that uses a rectifier circuit to transform alternating current from the electrical grid (mains AC) to direct current (DC) suitable for recharging the EV's battery pack. Cost and thermal issues limit how much power the rectifier can handle, so beyond around 240 V AC and 75 A it is better for an external charging station to deliver DC to the battery. Given these limits, most conventional charging designs are based on 240V, 30A
CHAdeMO
similar levels of DC since the alternating fluctuations can cause the heart to lose coordination, inducing ventricular fibrillation, a deadly loss of heart rhythm that must be corrected immediately. Any practical distribution system will use voltage levels sufficient for a dangerous amount of current to flow, whether it uses alternating or direct current. As precautions against electrocution are similar for both AC and DC, the technical and economic advantages of AC power transmission outweighed this theoretical risk, and it was eventually adopted as the standard worldwide. The advantage of AC for distributing power over a distance is due to the
War of the currents
unknown spectral phase of the pulse can be extracted using a simple, direct algebraic algorithm first described by Takeda. The first step involves Fourier transforming the interferogram into the pseudo time domain: where formula_9 is a 'direct current' (dc) term centred at formula_10 with a width inversely proportional to the spectral bandwidth, and formula_11 are two 'alternating current' (ac) sidebands resulting from the interference of the two fields. The dc term contains information about the spectral intensity only, whereas the ac sidebands contain information about the spectral intensity and phase of the pulse (since the ac sidebands are Hermitian conjugates
Spectral phase interferometry for direct electric-field reconstruction
operate with power conversion in either direction. Power conversion from AC to DC is called "rectification" and conversion from DC to AC is called "inversion". The direct current equipment often includes a coil (called a "reactor") that adds inductance in series with the DC line to help smooth the direct current. The inductance typically amounts to between 0.1 H and 1 H. The smoothing reactor can have either an air-core or an iron-core. Iron-core coils look like oil-filled high voltage transformers. Air-core smoothing coils resemble, but are considerably larger than, carrier frequency choke coils in high voltage transmission lines and
HVDC converter station
lighting was a growing business with many companies building outdoor direct current (DC) and alternating current (AC) arc lighting based street lighting systems and Thomas Edison launching the first DC electric utility designed to light homes and businesses with his patented incandescent bulb. In 1884 Westinghouse started developing his own DC domestic lighting system and hired physicist William Stanley to work on it. Westinghouse became aware of the new European alternating current systems in 1885 when he read about them in the UK technical journal "Engineering". AC had the ability to be "stepped up" in voltage by a transformer for
George Westinghouse
Some of the viaducts and tunnels on this line are considered outstanding achievements in Civil Engineering and are among the finest works in the world.” Till early-2007 Direct Current (DC) was used to pull trains in this sector. on 2007-05-25, the first Alternating Current (AC) 4,800 tonne goods train was hauled through this region. AC has a traction of 25,000 volts as compared to 1,500 volts of DC. When it was under Direct Current 58 wagon trains used to be detached into two separate units, and lugged separately. Now six AC locomotives pull the entire train. Winding around the railway
Thal Ghat
that creates a circumferential traveling field to which the rotor's magnetic poles rapidly synchronize. Some stepping motors have a similar structure. AC motor An AC motor is an electric motor driven by an alternating current (AC). The AC motor commonly consists of two basic parts, an outside stator having coils supplied with alternating current to produce a rotating magnetic field, and an inside rotor attached to the output shaft producing a second rotating magnetic field. The rotor magnetic field may be produced by permanent magnets, reluctance saliency, or DC or AC electrical windings. Less common, AC linear motors operate on
AC motor
AC motor An AC motor is an electric motor driven by an alternating current (AC). The AC motor commonly consists of two basic parts, an outside stator having coils supplied with alternating current to produce a rotating magnetic field, and an inside rotor attached to the output shaft producing a second rotating magnetic field. The rotor magnetic field may be produced by permanent magnets, reluctance saliency, or DC or AC electrical windings. Less common, AC linear motors operate on similar principles as rotating motors but have their stationary and moving parts arranged in a straight line configuration, producing linear motion
AC motor
detectors. Rectifiers are constructed from diodes, where they are used to convert alternating current (ac) electricity into direct current (dc). Automotive alternators are a common example, where the diode, which rectifies the AC into dc, provides better performance than the commutator or earlier, dynamo. Similarly, diodes are also used in "Cockcroft–Walton voltage multipliers" to convert ac into higher ac voltages. Diodes are frequently used to conduct damaging high voltages away from sensitive electronic devices. They are usually reverse-biased (non-conducting) under normal circumstances. When the voltage rises above the normal range, the diodes become forward-biased (conducting). For example, diodes are used
Diode
White Bay Power Stations, which were linked by a 6600 V transmission network and fed railway and tramway sub-feeder stations. Following the initial 600 V direct current (DC) installation, Ultimo Power Station supplied three phase alternating current (AC) at 6600 V, 25 cycles per second. Originally, this current was not stepped up for transmission. Rotary converters were used to convert the three phase AC to 600 V DC for the tram supply. The 1500 V DC heavy rail electrification commenced operation in 1926 and also initially used high capacity rotary converters. A 25–50 Hz frequency changer was installed at White
Ultimo Power Station
ventilation slots, though some have provision for forced air cooling from an external supply. Hysteresis and Eddy Current dynamometers are two of the most useful technologies in small ( and less) dynamometers. Electric motor/generator dynamometers are a specialized type of adjustable-speed drive. The absorption/driver unit can be either an alternating current (AC) motor or a direct current (DC) motor. Either an AC motor or a DC motor can operate as a generator that is driven by the unit under test or a motor that drives the unit under test. When equipped with appropriate control units, electric motor/generator dynamometers can be
Dynamometer
Traction substation A traction substation, traction current converter plant or traction power substation (TPSS) is an electrical substation that converts electric power from the form provided by the electrical power industry for public utility service to an appropriate voltage, current type and frequency to supply railways, trams (streetcars) or trolleybuses with traction current. These systems can be used to convert three-phase 50Hz or 60Hz alternating current (AC) for the supply of AC railway electrification systems at a lower frequency and single phase, as used by many older systems, or to rectify AC into direct current (DC) for those systems (primarily
Traction substation
field coils. The basic construction of the rotary converter consists of a DC generator (dynamo) with a set of slip rings tapped into its rotor windings at evenly spaced intervals. When a dynamo is spun the electric currents in its rotor windings alternate as it rotates in the magnetic field of the stationary field windings. This alternating current is rectified by means of a commutator which allows DC current to be extracted from the rotor. This principle is taken advantage of by energizing the same rotor windings with AC power which causes the machine to act as a synchronous AC
Rotary converter
of solar panels or photovoltaics. It can first be used in agriculture as a power source for irrigation. In health care solar panels can be used to refrigerate medical supplies. It can also be used for infrastructure. PV modules are used in photovoltaic systems and include a large variety of electric devices: Solar panel has been a well-known method of generating clean, emission free electricity. However, it produces only direct current electricity (DC), which is not what normal appliances use. Solar photovoltaic systems (solar PV systems) are often made of solar PV panels (modules) and inverter (changing DC to AC).
Solar panel
Power inverter A power inverter, or inverter, is an electronic device or circuitry that changes direct current (DC) to alternating current (AC). The input voltage, output voltage and frequency, and overall power handling depend on the design of the specific device or circuitry. The inverter does not produce any power; the power is provided by the DC source. A power inverter can be entirely electronic or may be a combination of mechanical effects (such as a rotary apparatus) and electronic circuitry. Static inverters do not use moving parts in the conversion process. Circuitry that performs the opposite function, converting AC
Power inverter
Plasma torch A plasma torch (also known as a plasma arc, plasma gun, or plasma cutter, plasmatron) is a device for generating a directed flow of plasma. The plasma jet can be used for applications including plasma cutting, plasma arc welding, plasma spraying, and plasma gasification for waste disposal. Thermal plasmas are generated in plasma torches by direct current (DC), alternating current (AC), radio-frequency (RF) and other discharges. DC torches are the most commonly used and researched, because when compared to AC: “there is less flicker generation and noise, a more stable operation, better control, a minimum of two electrodes,
Plasma torch
offset between a probe tip and a surface can be measured using the same principle as a macroscopic Kelvin probe. The cantilever in the AFM is a reference electrode that forms a capacitor with the surface, over which it is scanned laterally at a constant separation. The cantilever is not piezoelectrically driven at its mechanical resonance frequency ω as in normal AFM although an alternating current (AC) voltage is applied at this frequency. When there is a direct-current (DC) potential difference between the tip and the surface, the AC+DC voltage offset will cause the cantilever to vibrate. The origin of
Kelvin probe force microscope
principal disadvantage of DC bias was that it left the tape with a net magnetization, which generated significant noise on replay because of the grain of the tape particles. Some early DC-bias systems used a permanent magnet that was placed near the record head. It had to be swung out of the way for replay. DC bias was replaced by AC bias but was later re-adopted by some very low-cost cassette recorders. Although the improvements with DC bias were significant, an even better recording is possible if an AC (alternating current) bias is used instead. While several people around the
Tape bias
Tape bias Tape bias is the term for two techniques, AC bias and DC bias, that improve the fidelity of analogue tape recorders. DC bias is the addition of a direct current to the audio signal that is being recorded. AC bias is the addition of an inaudible high-frequency signal (generally from 40 to 150 kHz) to the audio signal. Most contemporary tape recorders use AC bias. When recording, magnetic tape has a nonlinear response as determined by its coercivity. Without bias, this response results in poor performance especially at low signal levels. A recording signal which generates a magnetic
Tape bias
area of , of which is land and (2.0%) is water. As of the census of 2000, there were 2,308 people, 963 households, and 659 families residing in the county. The population density was 2 people per square mile (1/km²). There were 1,193 housing units at an average density of 1 per square mile (0/km²). The racial makeup of the county was 99.18% White, 0.09% Black or African American, 0.13% Native American, 0.17% Asian, 0.13% from other races, and 0.30% from two or more races. 0.69% of the population were Hispanic or Latino of any race. 75.0% were of German,
Logan County, North Dakota
and is managed by Virgin Trains, who provide services between Liverpool Lime Street and London Euston. West Midlands Trains run a service between Liverpool and Birmingham New Street that calls at the station. Runcorn East station, located in the Murdishaw district of the new town, is managed by Transport for Wales, and provides services to Warrington, Manchester, Chester and North Wales. Runcorn is from Liverpool John Lennon Airport and from Manchester Airport. The town has two senior football teams – Runcorn Linnets FC and Runcorn Town FC. It also has a Sunday League and a Junior League. There is an
Runcorn
taught himself to draw and paint. On a French government scholarship in the early 1950s he lived in Paris, to which he often returned. Both in Europe and beyond, the highly influential French critic and curator Michel Tapié enthusiastically promoted the work of Antoni Tàpies. In 1948, Tàpies helped co-found the first Post-War Movement in Spain known as "Dau al Set" which was connected to the Surrealist and Dadaist Movements. The main leader and founder of "Dau al Set" was the poet Joan Brossa. The movement also had a publication of the same name, "Dau al Set". Tàpies started as
Antoni Tàpies
grandfather. The following chapters revolve around the Lycian lords Eliwood, Hector and their party, which the tactician, (and eventually Lyn) joins. The group are hunting down an antagonistic faction known as the Black Fang, a group of assassins based in Bern. The Black Fang, manipulated by a mysterious figure named Nergal, are attempting to provoke a full-scale war in Elibe, providing Nergal with an enormous amount of "quintessence", or life-force from fallen warriors. Nergal creates his morphs, artificial beings with jet-black hair and golden eyes, to remotely control the Black Fang, and to obtain the quintessence for him. The Black
Fire Emblem (video game)
in the event. In March 2016, she improved her record to 49.43 s. At the Duel in the Pool meeting in December 2015, Worrell broke the world record in the 4×100 meter medley relay (short course) together with her teammates Courtney Bartholomew, Katie Meili, and Simone Manuel. At the US Olympic Swimming Trials, Worrell placed first in the 100-meter butterfly and qualified for the US Olympic team. In Rio de Janeiro, Worrell placed 4th in the heats of the 100-meter butterfly but failed to qualify for the finals after finishing 9th in the semi-finals. She won a gold medal in
Kelsi Dahlia
accurately calculate true power (watts), apparent power (VA) power factor, AC voltage, AC current, DC voltage, DC current, frequency, IEC61000-3-2/3-12 Harmonic measurement, IEC61000-3-3/3-11 flicker measurement, individual phase voltages in delta applications where there is no neutral line, total harmonic distortion, phase and amplitude of individual voltage or current harmonics, etc. English-language power engineering students are advised to remember: "ELI the ICE man" or "ELI on ICE" – the voltage E leads the current I in an inductor L; the current leads the voltage in a capacitor C. Another common mnemonic is CIVIL – in a capacitor (C) the current (I)
Power factor
Stirring devices are close relatives of ratchet systems. The latter are defined in this context as AC driven spatially periodic arrays, where DC current is induced. It is possible to induce a DC current by applying a bias, or if the particles are charged then by applying an electro-motive-force. In contrast to that a quantum pumping mechanism produces a DC current in response to a cyclic deformation of the confining potential. In order to have a DC current from an AC driving, time reversal symmetry (TRS) should be broken. In the absence of magnetic field and dissipation it is the
Quantum stirring, ratchets, and pumping
motor. The rotation of the energized coils excites the stationary field windings producing part of the DC current. The other part is AC current from the slip rings which is directly rectified into DC by the commutator. This makes the rotary converter a hybrid dynamo and mechanical rectifier. When used in this way it is referred to as a synchronous rotary converter or simply a synchronous converter. The AC slip rings also allow the machine to act as an alternator. The device can be reversed and DC applied to the field and commutator windings to spin the machine and produce
Rotary converter
set of vibrator contacts on the transformer core, operated by its magnetic field, to repeatedly break the DC battery current to create a pulsing AC to power the transformer. Then a second set of rectifier contacts on the vibrator rectified the high AC voltage from the transformer secondary to DC. A "motor-generator set", or the similar "rotary converter", is not strictly a rectifier as it does not actually "rectify" current, but rather "generates" DC from an AC source. In an "M-G set", the shaft of an AC motor is mechanically coupled to that of a DC generator. The DC generator
Rectifier
the "converter". Almost all HVDC converters are inherently capable of converting from AC to DC ("rectification") and from DC to AC ("inversion"), although in many HVDC systems, the system as a whole is optimized for power flow in only one direction. Irrespective of how the converter itself is designed, the station that is operating (at a given time) with power flow from AC to DC is referred to as the "rectifier" and the station that is operating with power flow from DC to AC is referred to as the "inverter". Early HVDC systems used electromechanical conversion (the Thury system) but
High-voltage direct current
Alternating current direct current
Title: Alternating current. Content: Alternating current Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, fans and electric lamps into a wall socket. A common source of DC power is a battery cell in a flashlight. The abbreviations "AC" and "DC" are often used to mean simply "alternating" and "direct", as when they modify "current" or "voltage".
Alternating Current Direct Current
Alternating Current Direct Current
alternating current/direct current
Alternating Current and Direct Current
alternating current/direct current
Alternating Current and Direct Current