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Gilbert (unit)
The gilbert (symbol: Gb) is a unit used in practical cgs and CGS-EMU systems to measure magnetomotive force. The unit is named for English physicist William Gilbert. Definition: *1 Gb = (1/4π) Bi- t Conversion to the corresponding quantity in the SI, with the unit ampere-turn The ampere-turn (symbol A⋅t) is the MKS system of units, MKS (metre–kilogram–second) unit of magnetomotive force (MMF), represented by a direct current of one ampere flowing in a single-turn loop. ''Turns'' refers to the winding number of an ... (A⋅t): *1 Gb ≘ (10/4π) A-turn ≈ 0.7957747 A⋅t *1 A-turn ≘ 4π × 10−1 Gb References {{CGS units Magnetism Obsolete units of measurement Centimetre–gram–second system of units ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Unit Of Measurement
A unit of measurement, or unit of measure, is a definite magnitude (mathematics), magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of that kind can be expressed as a multiple of the unit of measurement. For example, a length is a physical quantity. The metre (symbol m) is a unit of length that represents a definite predetermined length. For instance, when referencing "10 metres" (or 10 m), what is actually meant is 10 times the definite predetermined length called "metre". The definition, agreement, and practical use of units of measurement have played a crucial role in human endeavour from early ages up to the present. A multitude of System of measurement, systems of units used to be very common. Now there is a global standard, the International System of Units (SI), the modern form of the metric system. In trade, weights and measures are often a su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Centimetre–gram–second System Of Units
The centimetre–gram–second system of units (CGS or cgs) is a variant of the metric system based on the centimetre as the unit of length, the gram as the unit of mass, and the second as the unit of time. All CGS mechanical units are unambiguously derived from these three base units, but there are several different ways in which the CGS system was extended to cover electromagnetism. The CGS system has been largely supplanted by the MKS system based on the metre, kilogram, and second, which was in turn extended and replaced by the International System of Units (SI). In many fields of science and engineering, SI is the only system of units in use, but CGS is still prevalent in certain subfields. In measurements of purely mechanical systems (involving units of length, mass, force, energy, pressure, and so on), the differences between CGS and SI are straightforward: the unit-conversion factors are all powers of 10 as and . For example, the CGS unit of force is the dyne, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Magnetomotive Force
In physics, the magnetomotive force (abbreviated mmf or MMF, symbol \mathcal F) is a quantity appearing in the equation for the magnetic flux in a magnetic circuit, Hopkinson's law. It is the property of certain substances or phenomena that give rise to magnetic fields: \mathcal = \Phi \mathcal , where is the magnetic flux and \mathcal is the reluctance of the circuit. It can be seen that the magnetomotive force plays a role in this equation analogous to the voltage in Ohm's law, , since it is the cause of magnetic flux in a magnetic circuit: # \mathcal = NI where is the number of turns in a coil and is the electric current through the coil. # \mathcal = \Phi \mathcal where is the magnetic flux and \mathcal is the magnetic reluctance # \mathcal = HL where is the magnetizing force (the strength of the magnetizing field) and is the mean length of a solenoid or the circumference of a toroid. Units The SI unit of mmf is the ampere, the same as the unit of current (analog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
William Gilbert (astronomer)
William Gilbert (; 24 May 1544? – 30 November 1603), also known as Gilberd, was an English physician, physicist and natural philosophy, natural philosopher. He passionately rejected both the prevailing Aristotelian philosophy and the Scholasticism, Scholastic method of university teaching. He is remembered today largely for his book ''De Magnete'' (1600). A unit of magnetomotive force, also known as magnetic scalar potential, magnetic potential, was named the ''Gilbert (unit), Gilbert'' in his honour; it has now been superseded by the Ampere-turn. Life and work Gilbert was born in Colchester to Jerome Gilberd, a borough Recorder (judge), recorder. He was educated at St John's College, Cambridge. After gaining his Doctor of Medicine, MD from Cambridge in 1569, and a short spell as bursar of St John's College, he left to practice medicine in London, and he travelled on the continent. In 1573, he was elected a Fellow of the Royal College of Physicians. In 1600, he was elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Biot (unit)
The abampere (abA), also called the biot (Bi) after Jean-Baptiste Biot, is the Centimetre–gram–second system of units#CGS approach to electromagnetic units, derived Electromagnetism, electromagnetic physical unit, unit of electric current in the Centimetre–gram–second system of units#Electromagnetic units (EMU), emu-cgs system of units (electromagnetic cgs). One abampere corresponds to ten amperes in the SI units, SI system of units. An abampere of current in a circular path of one centimeter radius produces a magnetic field of 2π oersteds at the center of the circle. The name abampere was introduced by Arthur E._Kennelly, Kennelly in 1903 as a short name for the long name ''(absolute) electromagnetic cgs unit of current'' that was in use since the adoption of the cgs system in 1875.A.E. Kennelly (1903"Magnetic units and other subjects that might occupy attention at the next international electrical congress"''20th Annual Convention of the American Institute of Elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Number Of Turns
A number is a mathematical object used to count, measure, and label. The most basic examples are the natural numbers 1, 2, 3, 4, and so forth. Numbers can be represented in language with number words. More universally, individual numbers can be represented by symbols, called ''numerals''; for example, "5" is a numeral that represents the number five. As only a relatively small number of symbols can be memorized, basic numerals are commonly organized in a numeral system, which is an organized way to represent any number. The most common numeral system is the Hindu–Arabic numeral system, which allows for the representation of any non-negative integer using a combination of ten fundamental numeric symbols, called digits. In addition to their use in counting and measuring, numerals are often used for labels (as with telephone numbers), for ordering (as with serial numbers), and for codes (as with ISBNs). In common usage, a ''numeral'' is not clearly distinguished from the ''numb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Ampere-turn
The ampere-turn (symbol A⋅t) is the MKS system of units, MKS (metre–kilogram–second) unit of magnetomotive force (MMF), represented by a direct current of one ampere flowing in a single-turn loop. ''Turns'' refers to the winding number of an electrical conductor composing an electromagnetic coil. For example, a current of flowing through a coil of 10 turns produces an MMF of . The corresponding physical quantity is ''NI'', the product of the number of turns, ''N'', and the current, ''I''; it has been used in industry, specifically, US-based Electromagnetic coil, coil-making industries. By maintaining the same current and increasing the number of loops or turns of the coil, the strength of the magnetic field increases because each loop or turn of the coil sets up its own magnetic field. The magnetic field unites with the fields of the other loops to produce the field around the entire coil, making the total magnetic field stronger. The strength of the magnetic field is no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Magnetism
Magnetism is the class of physical attributes that occur through a magnetic field, which allows objects to attract or repel each other. Because both electric currents and magnetic moments of elementary particles give rise to a magnetic field, magnetism is one of two aspects of electromagnetism. The most familiar effects occur in ferromagnetic materials, which are strongly attracted by magnetic fields and can be magnetized to become permanent magnets, producing magnetic fields themselves. Demagnetizing a magnet is also possible. Only a few substances are ferromagnetic; the most common ones are iron, cobalt, nickel, and their alloys. All substances exhibit some type of magnetism. Magnetic materials are classified according to their bulk susceptibility. Ferromagnetism is responsible for most of the effects of magnetism encountered in everyday life, but there are actually several types of magnetism. Paramagnetic substances, such as aluminium and oxygen, are weakly attracted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Obsolete Units Of Measurement
This is a list of obsolete units of measurement, organized by type. These units of measurement are typically no longer used, though some may be in limited use in various regions. For units of measurement that are unusual but not necessarily obsolete, see List of unusual units of measurement. For units of measurement that are humorous in nature, see List of humorous units of measurement. Area * Antsingae – a unit of area, smaller than the bunarium. * Bunarium (plural "bunaria") – a unit of area, equal to about 120 Hectare#Are, ares or 12,000 square metres * Carucate * Cawnie * Decimal (unit), Decimal * Dessiatin * Ground (unit), Ground * Hide (unit), Hide * Juchart * Jugerum * Katha (unit), Katha * Lessa (unit), Lessa or Lecha * Marabba * Morgen * Oxgang * Pari (unit), Pari – a unit of area equal to about 1 hectare * Quinaria * Tathe * Virgate Energy, etc. * Poncelet – unit of power * Sthène – unit of force * * Length * Ald (unit), Ald * Alen (unit of length), Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
