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Mouse Mill Motor
Froment's "mouse mill" motor was an early form of electric motor, also known as the Revolving Armature Engine. It has similarities to both the synchronous motor and the contemporary stepper motor. As the mouse mill motor was simple to construct and its speed could easily be governed, it was later used to drive automatic recorders in telegraphy. The name derives from the rotor's resemblance to a small treadmill. Their usual size was more to the scale of a hamster than a mouse, but rodents were more common at the time as domestic pests, not domestic pets. Construction The motor consists of a freely rotating Rotor (electric), rotor, surrounded by a number of electromagnets. The rotor is made of a light brass wheel, with a number of soft iron bars or "attractors" mounted around its rim and parallel to the axis. There may be one, two or four electromagnets mounted on the frame of the motor, together with a cam-operated switch for each magnet. Many of the early motors were made ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Attraction
Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments. Magnetism is one aspect of the combined phenomena 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, and nickel and their alloys. The rare-earth metals neodymium and samarium are less common examples. The prefix ' refers to iron because permanent magnetism was first observed in lodestone, a form of natural iron ore called magnetite, Fe3O4. All substances exhibit some type of m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Le Cour
Paul may refer to: *Paul (given name), a given name (includes a list of people with that name) * Paul (surname), a list of people People Christianity *Paul the Apostle (AD c.5–c.64/65), also known as Saul of Tarsus or Saint Paul, early Christian missionary and writer * Pope Paul (other), multiple Popes of the Roman Catholic Church * Saint Paul (other), multiple other people and locations named "Saint Paul" Roman and Byzantine empire * Lucius Aemilius Paullus Macedonicus (c. 229 BC – 160 BC), Roman general * Julius Paulus Prudentissimus (), Roman jurist * Paulus Catena (died 362), Roman notary *Paulus Alexandrinus (4th century), Hellenistic astrologer * Paul of Aegina or Paulus Aegineta (625–690), Greek surgeon Royals *Paul I of Russia (1754–1801), Tsar of Russia *Paul of Greece (1901–1964), King of Greece Other people *Paul the Deacon or Paulus Diaconus (c. 720 – c. 799), Italian Benedictine monk *Paul (father of Maurice), the father of Maurice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morse Code
Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one of the inventors of the telegraph. International Morse code encodes the 26 basic Latin letters through , one accented Latin letter (), the Arabic numerals, and a small set of punctuation and procedural signals ( prosigns). There is no distinction between upper and lower case letters. Each Morse code symbol is formed by a sequence of ''dits'' and ''dahs''. The ''dit'' duration is the basic unit of time measurement in Morse code transmission. The duration of a ''dah'' is three times the duration of a ''dit''. Each ''dit'' or ''dah'' within an encoded character is followed by a period of signal absence, called a ''space'', equal to the ''dit'' duration. The letters of a word are separated by a space of duration equal to three ''dits'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Influence Machine
An electrostatic generator, or electrostatic machine, is an electrical generator that produces ''static electricity'', or electricity at high voltage and low continuous current. The knowledge of static electricity dates back to the earliest civilizations, but for millennia it remained merely an interesting and mystifying phenomenon, without a theory to explain its behavior and often confused with magnetism. By the end of the 17th century, researchers had developed practical means of generating electricity by friction, but the development of electrostatic machines did not begin in earnest until the 18th century, when they became fundamental instruments in the studies about the new science of electricity. Electrostatic generators operate by using manual (or other) power to transform mechanical work into electric energy, or using electric currents. Manual electrostatic generators develop electrostatic charges of opposite signs rendered to two conductors, using only electric forces, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galvanometer
A galvanometer is an electromechanical measuring instrument for electric current. Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the flow of current more precisely. A galvanometer works by deflecting a pointer in response to an electric current flowing through a coil in a constant magnetic field. Galvanometers can be thought of as a kind of actuator. Galvanometers came from the observation, first noted by Hans Christian Ørsted in 1820, that a magnetic compass's needle deflects when near a wire having electric current. They were the first instruments used to detect and measure small amounts of current. André-Marie Ampère, who gave mathematical expression to Ørsted's discovery, named the instrument after the Italian electricity researcher Luigi Galvani, who in 1791 discovered the principle of the frog galvanoscope – that electric current would make the legs of a dead frog jerk. Galvanometers have bee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syphon Recorder
The syphon or siphon recorder is an obsolete electromechanical device used as a receiver for submarine telegraph cables invented by William Thomson, 1st Baron Kelvin in 1867. It automatically records an incoming telegraph message as a wiggling ink line on a roll of paper tape. Later a trained telegrapher would read the tape, translating the pulses representing the "dots" and "dashes" of the Morse code to characters of the text message. The syphon recorder replaced Thomson’s previous invention, the mirror galvanometer as the standard receiving instrument for submarine telegraph cables, allowing long cables to be worked using just a few volts at the sending end. The disadvantage of the mirror galvanometer was that it required two operators, one with a steady eye to read and call off the signal, the other to write down the characters received. Its use spread to ordinary telegraph lines and radiotelegraphy radio receivers. A major advantage of the syphon recorder was that no oper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Muirhead
Alexander Muirhead, FRS, (26 May 1848 – 13 December 1920) born in East Saltoun, East Lothian, Scotland was an electrical engineer specialising in wireless telegraphy. Biography Muirhead studied for his Bachelor of Science at University College London and then DSc (in electricity) at St Bartholomew's Hospital 1869–1872 where he is credited with recording the first human electrocardiogram. He was scientific adviser to his father's company, Latimer Clark, Muirhead & Co., designing precision instruments, and with H A Taylor patented a method of duplexing telegraph signals for use in submarine cables. He later worked with Sir Oliver Lodge on the development of wireless telegraphy, selling their important tuning patents to Marconi in 1912. He became a member of the Institution of Electrical Engineers in 1877, and was elected a Fellow of the Royal Society in 1904. He died at Shortlands, Kent, on 13 December 1920 and is buried at West Norwood Cemetery. References External l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lord Kelvin
William Thomson, 1st Baron Kelvin, (26 June 182417 December 1907) was a British mathematician, Mathematical physics, mathematical physicist and engineer born in Belfast. Professor of Natural Philosophy (Glasgow), Professor of Natural Philosophy at the University of Glasgow for 53 years, he did important work in the mathematical analysis of electricity and formulation of the first and second laws of thermodynamics, and did much to unify the emerging discipline of physics in its contemporary form. He received the Royal Society's Copley Medal in 1883, was its President of the Royal Society, president 1890–1895, and in 1892 was the first British scientist to be elevated to the House of Lords. Absolute temperatures are stated in units of kelvin in his honour. While the existence of a coldest possible temperature (absolute zero) was known prior to his work, Kelvin is known for determining its correct value as approximately −273.15 degrees Celsius or −459.67 degrees Fahrenheit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telegraphy
Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas pigeon post is not. Ancient signalling systems, although sometimes quite extensive and sophisticated as in China, were generally not capable of transmitting arbitrary text messages. Possible messages were fixed and predetermined and such systems are thus not true telegraphs. The earliest true telegraph put into widespread use was the optical telegraph of Claude Chappe, invented in the late 18th century. The system was used extensively in France, and European nations occupied by France, during the Napoleonic era. The electric telegraph started to replace the optical telegraph in the mid-19th century. It was first taken up in Britain in the form of the Cooke and Wheatstone telegraph, initially used mostly as an aid to railway signalling. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul-Gustave Froment
Paul-Gustave Froment (born March 3, 1815 in Paris, died 1865) was a French mechanic, instrument maker and inventor. Life He was born in Paris and was educated at the Collège Sainte-Barbe and the Lycée Louis-le-Grand. Having demonstrated from childhood talent for technology, his father decided to let him study at the Ecole Polytechnique in Paris. He later moved to Britain to continue his studies in Manchester. He was also one of the earliest photographers, working with the Direct Positive Process. On his return to France, his intention was to build steam engines but he was prevented from doing so by lack of funds. Instead, he opened a Paris workshop in 1844 where, among other things, he worked on a telegraph with written and keyboard signals, improved Gaetan Bonelli's electric loom, and helped William Hughes improve his early typewriter. He also worked on the gyroscope with Léon Foucault, for whom he also made the pendulum for his famous demonstration in 1851. In 1854 h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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