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Telephone Magneto
A telephone magneto is a hand-cranked electrical generator that uses permanent magnets to produce alternating current from a rotating armature. In early telegraphy, magnetos were used to power instruments, while in telephony they were used to generate electrical current to drive electromechanical ringers in telephone sets and activate signals on operator consoles. Telegraphy Telegraphy pre-dated telephony and magnetos were used to drive some of the early printing telegraph instruments. Manual telegraphy with keys and reception by either a needle instrument or a syphon recorder could be powered by batteries. The later automatic and printing instruments, such as the Wheatstone ABC telegraph, required greater currents that could be delivered by a hand-cranked magneto. A hand-crank was used to rotate a belt drive that increases the rotational speed of an armature with a pair of coils between the poles of a stationary horseshoe magnet. Telephony Many early manual telephones had ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Magneto From Beneath
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals that are transmitted via cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from el, τῆλε (''tēle'', ''far'') and φωνή (''phōnē'', ''voice''), together meaning ''distant voice''. A common short form of the term is ''phone'', which came into use early in the telephone's history. In 1876, Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice at a second device. This instrument was further developed by many others, and became rapidly indispensable in business, government, and in households. The essential elements of a telephone are a micr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ericsson Taxen (2)
(lit. "Telephone Stock Company of LM Ericsson"), commonly known as Ericsson, is a Swedish multinational networking and telecommunications company headquartered in Stockholm. The company sells infrastructure, software, and services in information and communications technology for telecommunications service providers and enterprises, including, among others, 3G, 4G, and 5G equipment, and Internet Protocol (IP) and optical transport systems. The company employs around 100,000 people and operates in more than 180 countries. Ericsson has over 57,000 granted patents. Ericsson has been a major contributor to the development of the telecommunications industry and is one of the leaders in 5G. The company was founded in 1876 by Lars Magnus Ericsson and is jointly controlled by the Wallenberg family through its holding company Investor AB, and the universal bank Handelsbanken through its investment company Industrivärden. The Wallenbergs and the Handelsbanken sphere acquired their v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ringer Box
A ringer box is a telephone signaling device, similar to a bell box. It usually contains an electromechanical gong and was used with most early desk stand telephones, such as candlestick telephones and the Western Electric type Western Electric hand telephone sets, which were too small to hold a ringer and other required electrical components. Many pay station telephones also used a separate ringer box. In telephony, ringer boxes and similar devices are often categorized as subscriber sets. The ringer contained in the ringer box alerts a call recipient to incoming calls by ringing one or more metallic bells emitting a ringtone. Ringers were commonly placed in the same housing as the subscriber set, which consisted of other electrical components, such as induction coils, capacitors, and, if required, a magneto generator. The subscriber set interfaced a telephone set to the telephone network, while magneto generators were used in a manual exchange to generate a remote ring sign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magneto
A magneto is an electrical generator that uses permanent magnets to produce periodic pulses of alternating current. Unlike a dynamo, a magneto does not contain a commutator to produce direct current. It is categorized as a form of alternator, although it is usually considered distinct from most other alternators, which use field coils rather than permanent magnets. Hand-cranked magneto generators were used to provide ringing current in telephone systems. Magnetos were also adapted to produce pulses of high voltage in the ignition systems of some gasoline-powered internal combustion engines to provide power to the spark plugs. Use of such ignition magnetos for ignition is now limited mainly to engines without a low-voltage electrical system, such as lawnmowers and chainsaws, and to aircraft engines, in which keeping the ignition independent of the rest of the electrical system ensures that the engine continues running in the event of alternator or battery failure. For redundancy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Public Switched Telephone Network
The public switched telephone network (PSTN) provides Communications infrastructure, infrastructure and services for public Telecommunications, telecommunication. The PSTN is the aggregate of the world's circuit-switched telephone networks that are operated by national, regional, or local telephony operators. These consist of telephone lines, fiber optic cables, microwave transmission links, Routing in cellular networks, cellular networks, communications satellites, and undersea telephone cables, all interconnected by switching centers which allow most telephones to communicate with each other. Originally a network of fixed-line Analog signal processing, analog telephone systems, the PSTN is now almost entirely digital in its core network and includes mobile and other networks, as well as fixed telephones. The technical operation of the PSTN adheres to the standards created by the ITU-T. These standards allow different networks in different countries to interconnect seamlessly. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc–carbon Battery
A zinc–carbon battery (or carbon zinc battery in U.S. English) is a dry cell primary battery that provides direct electric current from the electrochemical reaction between zinc and manganese dioxide (MnO2) in the presence of an electrolyte. It produces a voltage of about 1.5 volts between the zinc anode, which is typically constructed as a cylindrical container for the battery cell, and a carbon rod surrounded by a compound with a higher Standard electrode potential (positive polarity), known as the cathode, that collects the current from the manganese dioxide electrode. The name "zinc-carbon" is slightly misleading as it implies that carbon is acting as the oxidizing agent rather than the manganese dioxide. General-purpose batteries may use an acidic aqueous paste of ammonium chloride (NH4Cl) as electrolyte, with some zinc chloride solution on a paper separator to act as what is known as a salt bridge. ''Heavy-duty'' types use a paste primarily composed of zinc chloride (ZnC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Battery Sizes
This is a list of the sizes, shapes, and general characteristics of some common primary and secondary list of battery types, battery types in household, automotive and light industrial use. The complete nomenclature for a battery specifies size, chemistry, terminal arrangement, and special characteristics. The same physically interchangeable cell size or battery size may have widely different characteristics; physical interchangeability is not the sole factor in substituting a battery. The full battery designation identifies not only the size, shape and terminal layout of the battery but also the chemistry (and therefore the voltage per cell) and the number of cells in the battery. For example, a CR123 battery is always LiMnO2 ('Lithium') chemistry, in addition to its unique size. The following tables give the common battery chemistry types for the current common sizes of batteries. See Electric battery#Comparison, Battery chemistry for a list of other electrochemical systems ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Exchange
A telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital systems to establish telephone calls between subscribers. In historical perspective, telecommunication terms have been used with different semantics over time. The term ''telephone exchange'' is often used synonymously with ''central office'', a Bell System term. Often, a ''central office'' is defined as a building used to house the inside plant equipment of potentially several telephone exchanges, each serving a certain geographical area. Such an area has also been referred to as the exchange or exchange area. In North America, a central office location may also be identified as a ''wire center'', designating a facility to which a telephone is connected and obtains dial tone. For business and billing purposes, telecommunication carriers defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals that are transmitted via cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from el, τῆλε (''tēle'', ''far'') and φωνή (''phōnē'', ''voice''), together meaning ''distant voice''. A common short form of the term is ''phone'', which came into use early in the telephone's history. In 1876, Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice at a second device. This instrument was further developed by many others, and became rapidly indispensable in business, government, and in households. The essential elements of a telephone are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horseshoe Magnet
A horseshoe magnet is a magnet made in the shape of a horseshoe or a U-shape and has become the most widely recognized symbol for magnets. It was invented by William Sturgeon in 1825. This type of magnet can be either a permanent magnet or an electromagnet. The main advantage of a horseshoe magnet over other types of magnets is that the magnetic poles are close together creating a much stronger magnetic field. History In 1819, it was discovered that passing electric current through a piece of metal deflected a compass needle. Following this discovery, many other experiments surrounding magnetism were attempted. These experiments culminated in William Sturgeon wrapping wire around a horseshoe-shaped piece of iron and running electric current through the wires creating the first horseshoe magnet. This was also the first practical electromagnet and the first magnet that could lift more mass than the magnet itself when the seven-ounce magnet was able to lift nine pounds of ir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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