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Pole Piece
A pole piece is a structure composed of material of high magnetic permeability that serves to direct the magnetic field produced by a magnet. A pole piece attaches to and in a sense extends a magnet#Modelling magnets, pole of the magnet, hence the name. Pole pieces are used with both permanent magnets and electromagnets. In the case of an electromagnet, the pole piece or pieces simply extend the magnetic core and can even be regarded as part of it, particularly if they are made of the same material. In the case of a permanent magnet, the distinction between the magnet itself and the pole piece or pieces is more clear cut. Materials The traditional material for pole pieces was soft iron. While still often used with permanent magnets, soft iron suffers from eddy currents which make it less suitable for use with electromagnets, and particularly inefficient when the magnet is excited by alternating current. Shapes and forms Pole pieces take many shapes and forms depending on the a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromechanical Solenoid
upright=1.20, An illustration of a solenoid upright=1.20, Magnetic field created by a seven-loop solenoid (cross-sectional view) described using field lines A solenoid () is a type of electromagnet formed by a helix, helical coil of wire whose length is substantially greater than its diameter, which generates a controlled magnetic field. The coil can produce a uniform magnetic field in a volume of space when an electric current is passed through it. André-Marie Ampère coined the term ''solenoid'' in 1823, having conceived of the device in 1820. The French term originally created by Ampère is ''solénoïde'', which is a French transliteration of the Greek word '' σωληνοειδὴς'' which means ''tubular''. The helical coil of a solenoid does not necessarily need to revolve around a straight-line axis; for example, William Sturgeon's electromagnet of 1824 consisted of a solenoid bent into a horseshoe shape (similarly to an arc spring). Solenoids provide magnetic fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Armature (electrical Engineering)
In electrical engineering, the armature is the winding (or set of windings) of an electric machine which carries alternating current. The armature windings conduct Alternating current, AC even on Direct current, DC machines, due to the Commutator (electric), commutator action (which periodically reverses current direction) or due to electronic commutation, as in Brushless DC electric motor, brushless DC motors. The armature can be on either the Rotor (electric), rotor (rotating part) or the stator (field coil, stationary part), depending on the type of electric machine. Shapes of Armature (electrical engineering), armature used in motors include double-T and triple-T armatures. The armature windings interact with the magnetic field (magnetic flux) in the air-gap; the magnetic field is generated either by permanent magnets, or electromagnets formed by a conducting coil. The armature must carry electric current, current, so it is always a electrical conductor, conductor or a c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnet Keeper
A magnet keeper, also known historically as an armature, is a bar made from magnetically soft iron or steel, which is placed across the poles of a permanent magnet to help preserve the strength of the magnet by completing the magnetic circuit; it is important for magnets that have low magnetic coercivity, such as alnico magnets (0.07T). Keepers also have a useful safety function, as they stop external metal being attracted to the magnet. Many magnets do not need a keeper, such as neodymium magnets, as they have very high coercivities; only those with lower coercivities, meaning that they are more susceptible to stray fields, require keepers. A magnet can be considered as the sum of many small magnetic domains, which may be only a few microns or smaller in size. Each domain carries its own small magnetic field, which can point in any direction. When all the domains are pointing in the same direction, the fields add up, yielding a strong magnet. When these all point in random d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moving Coil Meter
Moving or Movin' may refer to: Moving of goods * Relocation (personal), the process of leaving one dwelling and settling in another * Relocation of professional sports teams * Relocation (computer science) * Structure relocation Music Albums * ''Moving'' (Peter, Paul and Mary album), 1963 * ''Moving'' (The Raincoats album), 1983 * ''Movin (Herman van Doorn album), 2001 * ''Movin (Jennifer Rush album), 1985 Songs * "Moving" (Kate Bush song), 1978 * "Moving" (Supergrass song), 1999 * "Moving" (Travis song), 2013 * "Moving", by Cathy Davey from ''Tales of Silversleeve'', 2007 * "Moving", by Ed Sheeran from '' -'', 2023 * "Moving", by Suede from ''Suede'', 1993 * "Movin (Brass Construction song), 1976 * "Movin (Mohombi song), 2014 * "Movin, by Skin from '' Fake Chemical State'', 2006 Other uses * ''Moving'' (1988 film), a comedy starring Richard Pryor * ''Moving'' (1993 film), a Japanese film * ''Moving'' (British TV series), a British sitcom starring Penelope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voice Coil
A voice coil (consisting of a former, collar, and winding) is the coil of wire attached to the apex of a loudspeaker cone. It provides the motive force to the cone by the reaction of a magnetic field to the current passing through it. The term is also used for voice coil linear motors such as those used to move the heads inside hard disk drives, which produce a larger force and move a longer distance but work on the same principle. In some applications, such as the operation of servo valves, electronic focus adjustment on digital cameras, these are known as voice coil motors (VCM). Operation By driving a current through the voice coil, a magnetic field is produced. This magnetic field causes the voice coil to react to the magnetic field from a permanent magnet fixed to the speaker's frame, thereby moving the cone of the speaker. By applying an audio waveform to the voice coil, the cone will reproduce the sound pressure waves, corresponding to the original input sig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Loudspeaker
An electrodynamic speaker driver, often called simply a speaker driver when the type is implicit, is an individual transducer that converts an electrical audio signal to sound waves. While the term is sometimes used interchangeably with the term '' speaker'' (''loudspeaker''), it is usually applied to specialized transducers that reproduce only a portion of the audible frequency range, or to the one or more drivers within a loudspeaker cabinet (or simply "speaker".). For high fidelity reproduction of sound, multiple loudspeakers are often mounted in the same enclosure, each reproducing a different part of the audible frequency range. In this case the individual speakers are referred to as ''drivers'' and the entire unit is called a ''loudspeaker''. Drivers made for reproducing high audio frequencies are called tweeters, those for middle frequencies are called mid-range drivers (much less commonly called squawkers), and those for low frequencies are called woofers, while ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alternating Current
Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, 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, Fan (machine), fans and electric lamps into a wall socket. The abbreviations ''AC'' and ''DC'' are often used to mean simply ''alternating'' and ''direct'', respectively, as when they modify ''Electric current, current'' or ''voltage''. The usual waveform of alternating current in most electric power circuits is a sine wave, whose positive half-period corresponds with positive direction of the current and vice versa (the full period is called a ''wave cycle, cycle''). "Alternating current" most commonly refers to power distribution, but a wide range of other appl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Permeability
In electromagnetism, permeability is the measure of magnetization produced in a material in response to an applied magnetic field. Permeability is typically represented by the (italicized) Greek letter ''μ''. It is the ratio of the magnetic induction B to the magnetizing field H in a material. The term was coined by William Thomson, 1st Baron Kelvin in 1872, and used alongside permittivity by Oliver Heaviside in 1885. The reciprocal of permeability is magnetic reluctivity. In SI units, permeability is measured in henries per meter (H/m), or equivalently in newtons per ampere squared (N/A2). The permeability constant ''μ''0, also known as the magnetic constant or the permeability of free space, is the proportionality between magnetic induction and magnetizing force when forming a magnetic field in a classical vacuum. A closely related property of materials is magnetic susceptibility, which is a dimensionless proportionality factor that indicates the degree of magnet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
