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87-476: 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

174-500: A flux switching alternator . These must operate at high speeds, directly coupled to a turbine. Both types share the advantage of the output coils being part of the stator, thus avoiding the need for brushgear. Telephone A telephone , colloquially referred to as a phone , 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

261-514: A ringer or a visual indicator, to announce an incoming telephone call. Telephone calls are initiated most commonly with a keypad or dial, affixed to the telephone, to enter a telephone number , which is the address of the call recipient's telephone in the telecommunications system, but other methods existed in the early history of the telephone. The first telephones were directly connected to each other from one customer's office or residence to another customer's location. Being impractical beyond just

348-408: A speaking tube . In the U.S., a somewhat dated slang term refers to the telephone as "the horn," as in "I couldn't get him on the horn," or "I'll be off the horn in a moment." Early telephones were technically diverse. Some used a water microphone , some had a metal diaphragm that induced current in an electromagnet wound around a permanent magnet, and some were dynamic – their diaphragm vibrated

435-400: A three-phase stator and a bridge rectifier to produce direct current (DC). This current either directly pumps water, is stored in batteries, or drives a mains inverter that can supply the commercial electricity grid . A typical design is an axial-flux generator recycled from a car brake disk and hub bearing. A MacPherson strut provides the azimuth bearing to bring the turbine into

522-439: A circle, in geometrical terms. Neighboring windings overlap, as can be seen in almost any modern motor or generator rotor that has a commutator. In addition, windings are placed into slots with a rounded shape (as seen from the end of the rotor). At the surface of the rotor, the slots are only as wide as needed to permit the insulated wire to pass through them while winding the coils. While the hollow ring could now be replaced with

609-497: A coil of wire in the field of a permanent magnet or the coil vibrated the diaphragm. The sound-powered dynamic variants survived in small numbers through the 20th century in military and maritime applications, where its ability to create its own electrical power was crucial. Most, however, used the Edison/Berliner carbon transmitter , which was much louder than the other kinds, even though it required an induction coil which

696-422: A common battery exchange had a magneto hand-cranked generator to produce a high voltage alternating signal to ring the bells of other telephones on the line and to alert the operator. Some local farming communities that were not connected to the main networks set up barbed wire telephone lines that exploited the existing system of field fences to transmit the signal. In the 1890s a new smaller style of telephone

783-414: A cranking battery, which may need more ignition timing control than a magneto system can provide, though sophisticated solid state controllers are becoming more common. Manual telephones for local battery station service in magneto exchanges were equipped with a hand-cranked magneto generator to produce an alternating voltage to alert the central office operator, or to ring the bells of other telephones on

870-485: A few customers, these systems were quickly replaced by manually operated centrally located switchboards . These exchanges were soon connected together, eventually forming an automated, worldwide public switched telephone network . For greater mobility, various radio systems were developed in the mid-20th century for transmission between mobile stations on ships and in automobiles. Hand-held mobile phones were introduced for personal service starting in 1973. In later decades,

957-402: A graph of the current produced as the ring spins one revolution. While no actual device uses this exact design, this diagram is a building block to better understand the next illustrations. A one-pole, two-coil Gramme ring. The second coil on the opposite side of the ring is wired in parallel with the first. Because the bottom coil is oriented opposite of the top coil, but both are immersed in

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1044-486: A home and a shop. Users who wanted the ability to speak to several different locations would need to obtain and set up three or four pairs of telephones. Western Union , already using telegraph exchanges, quickly extended the principle to its telephones in New York City and San Francisco , and Bell was not slow in appreciating the potential. Signalling began in an appropriately primitive manner. The user alerted

1131-565: A machine invented by Antonio Pacinotti in 1860, Gramme was the developer of a new induced rotor in form of a wire-wrapped ring ( Gramme ring ) and demonstrated this apparatus to the Academy of Sciences in Paris in 1871. Although popular in 19th century electrical machines, the Gramme winding principle is no longer used since it makes inefficient use of the conductors. The portion of the winding on

1218-476: A modern generator . During a demonstration at an industrial exposition in Vienna in 1873, Gramme accidentally discovered that this device, if supplied with a constant- voltage power supply, will act as an electric motor . Gramme's partner, Hippolyte Fontaine , carelessly connected the terminals of a Gramme machine to another dynamo which was producing electricity, and its shaft began to spin. The Gramme machine

1305-586: A new industry comprising many VoIP companies that offer services to consumers and businesses . The reported global VoIP market in October 2021 was $ 85.2 billion with a projection of $ 102.5 billion by 2026. IP telephony uses high-bandwidth Internet connections and specialized customer premises equipment to transmit telephone calls via the Internet, or any modern private data network. The customer equipment may be an analog telephone adapter (ATA) which translates

1392-424: A number of decades in the 19th century for electrical engineers to learn the importance of small air gaps. The Gramme ring, however, has a comparatively small air gap, which enhances its efficiency. (In the top illustration, the large hoop-like piece is the laminated permanent magnet; the Gramme ring is rather hard to see at the base of the hoop.) This illustration shows a simplified one-pole, one-coil Gramme ring and

1479-400: A numeric keypad for dialing, and a display for caller ID . In addition, answering machine function may be built in. The cordless handset contains a rechargeable battery , which the base station recharges when the handset rests in its cradle. Muilt-handset systems generally also have additional charging stands. A cordless telephone typically requires a constant electricity supply to power

1566-591: A satellite phone is that it can be used in such regions where local terrestrial communication infrastructures, such as landline and cellular networks, are not available. Satellite phones are popular on expeditions into remote locations, hunting, fishing, maritime sector, humanitarian missions, business trips, and mining in hard-to-reach areas, where there is no reliable cellular service. Satellite telephones rarely get disrupted by natural disasters on Earth or human actions such as war, so they have proven to be dependable communication tools in emergency situations, when

1653-431: A separate enclosure, called the subscriber set. The dial switch in the base interrupted the line current by repeatedly but very briefly disconnecting the line one to ten times for each digit, and the hook switch (in the center of the circuit diagram) disconnected the line and the transmitter battery while the handset was on the cradle. In the 1930s, telephone sets were developed that combined the bell and induction coil with

1740-415: A solid cylindrical core or drum , the ring still proves to be a more efficient design, because in a solid core the field lines concentrate in a thin surface region and minimally penetrate the center. For a very large power-generation armature several feet in diameter, using a hollow ring armature requires far less metal and is lighter than a solid core drum armature. The hollow center of the ring also provides

1827-410: A stack of individual magnets, but acts through a pair of pole pieces . Both dynamos and alternators required a source of power to drive their field coils. This could not be supplied by their own generator's output, without some process of ' bootstrapping '. Henry Wilde , an electrical engineer from Manchester, England, developed a combination of magneto and electro-magnet generator, where the magneto

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1914-418: A static magnetic field, creating brief spikes or pulses of DC resulting in a transient output of low average power, rather than a constant output of high average power. With more than a few coils on the Gramme ring armature, the resulting voltage waveform is practically constant, thus producing a near direct current supply. This type of machine needs only electromagnets producing the magnetic field to become

2001-472: A weak permanent magnet, and thus a magneto. The shunt wiring of the generator feeds some of its output current back into the field coils, which in turn increases output. Because of this, the field 'builds up' regeneratively, though this may take 20–30 seconds to do so fully. Use of magnetos here is now obsolete, though separate exciters are still used for high power generating sets, as they permit easier control of output power. These are particularly common with

2088-514: A wired interface, such as USB or Lightning connectors. Smartphones, being able to run apps , have vastly expanded functionality compared to previous mobile phones. Having internet access and built in cameras, smartphones have made video calling readily accessible via IP connections. Smartphones also have access to a large number of web services and web apps, giving them functionality similar to traditional computers, although smartphones are often limited by their relatively small screen size and

2175-474: Is connected to a commutator on which two brushes run. Permanent magnets magnetize the soft iron ring, producing a magnetic field which rotates around through the coils in order as the armature turns. This induces a voltage in two of the coils on opposite sides of the armature, which is picked off by the brushes. Earlier electromagnetic machines passed a magnet near the poles of one or two electromagnets, or rotated coils wound on double-T armatures within

2262-489: Is derived from the Greek : τῆλε , tēle , "far" and φωνή, phōnē , "voice", together meaning "distant voice". Credit for the invention of the electric telephone is frequently disputed. As with other influential inventions such as radio , television , the light bulb , and the computer , several inventors pioneered experimental work on voice transmission over a wire and improved on each other's ideas. New controversies over

2349-479: Is for powering lights and USB powered devices on bicycles. Most commonly, a small magneto, termed a bottle dynamo , rubs against the tire of the bicycle and generates power as the wheel turns. More expensive and less common but more efficient is the hub dynamo that rotates neodymium magnets around a copper coil in a claw pole cage inside the hub of a wheel. Commonly referred to as dynamos , both devices are in fact magnetos, producing alternating current as opposed to

2436-428: Is limited, usually to within the same building or within a short distance from the base station. Base stations include a radio transceiver which enables full-duplex, outgoing and incoming signals and speech with the handsets. The base station often includes a microphone, audio amplifier , and a loudspeaker to enable hands-free speakerphone conversations, without needing to use a handset. The base station may also have

2523-663: The Earth instead of terrestrial cell sites , as cellphones do. Therefore, they can work in most geographic locations on the Earth's surface, as long as open sky and the line-of-sight between the phone and the satellite is provided. Depending on the architecture of a particular system, coverage may include the entire Earth or only specific regions. Satellite phones provide similar functionality to terrestrial mobile telephones; voice calling , text messaging , and low-bandwidth Internet access are supported through most systems. The advantage of

2610-612: The Internet , giving rise to the field of Internet Protocol (IP) telephony, also known as voice over Internet Protocol (VoIP). VoIP has proven to be a disruptive technology that is rapidly replacing traditional telephone network infrastructure. By January 2005, up to 10% of telephone subscribers in Japan and South Korea had switched to this digital telephone service. A January 2005 Newsweek article suggested that Internet telephony may be "the next big thing." The technology has spawned

2697-502: The direct current produced by a true dynamo . The magneto also had a medical application for treatment of mental illness in the beginnings of electromedicine . In 1850, Duchenne de Boulogne , a French doctor, developed and manufactured a magneto with a variable outer voltage and frequency, through varying revolutions by hand or varying the inductance of the two coils, for clinical experiments in neurology . Magnetos adapted to produce impulses of high voltage for spark plugs are used in

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2784-490: The dynamo machine, which used an electromagnet to produce the magnetic field, was developed later. The machine built by Hippolyte Pixii in 1832 used a rotating permanent magnet to induce alternating voltage in two fixed coils. The first electrical machine used for an industrial process was a magneto, the Woolrich Electrical Generator . In 1842 John Stephen Woolrich was granted UK patent 9431 for

2871-402: 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 Ancient Greek : τῆλε , romanized :  tēle , lit.   'far' and φωνή ( phōnē , voice ), together meaning distant voice . In 1876, Alexander Graham Bell

2958-658: The 1990s, mobile phones have gained other features which are not directly related to their primary function as telephones. These include text messaging, calendars, alarm clocks, personal schedulers, cameras, music players, games and later, internet access and smartphone functionality. Nearly all mobile phones have the ability to send text messages to other users via the SMS (Short Message Service) protocol. The multimedia messaging service (MMS) protocol enables users to send and receive multimedia content, such as photos, audio files and video files. As their functionality has increased over

3045-493: The advent of smartphones, mobile phone manufacturers have also included consumer electronics companies, such as Apple , Samsung and Xiaomi . As of 2022, most mobile phones are smartphones, being a combination of a mobile phone and a personal computing device in the same unit. Most smartphones are primarily operated using a graphical user interface and a touch screen. Many phones have a secondary voice user interface, such as Siri on Apple iPhones , which can operate many of

3132-451: The analog cellular system evolved into digital networks with greater capability and lower cost. Convergence in communication services has provided a broad spectrum of capabilities in cell phones, including mobile computing, giving rise to the smartphone , the dominant type of telephone in the world today. Before the development of the electric telephone, the term telephone was applied to other inventions, and not all early researchers of

3219-401: The assistance of a telephone operator. What turned out to be the most popular and longest-lasting physical style of telephone was introduced in the early 20th century, including Bell's 202-type desk set. A carbon granule transmitter and electromagnetic receiver were united in a single molded plastic handle, which when not in use was secured in a cradle in the base unit. The circuit diagram of

3306-526: The base station and charger units by means of a DC transformer which plugs into a wall AC power outlet. A mobile phone or cellphone or hand phone is a handheld telephone which connects via radio transmissions to a cellular telephone network . The cellular network consists of a network of ground based transmitter/receiver stations with antennas – which are usually located on towers or on buildings – and infrastructure connecting to land-based telephone lines. Analog cellular networks first appeared in 1979, with

3393-404: The bell, induction coil, battery and magneto were in a separate bell box or " ringer box ". In phones connected to common battery exchanges, the ringer box was installed under a desk, or other out-of-the-way place, since it did not need a battery or magneto. Cradle designs were also used at this time, having a handle with the receiver and transmitter attached, now called a handset , separate from

3480-618: The bipolar dynamo, this did have the advantage of more poles giving a smoother output per rotation, which was an advantage when driving arc lamps. Magnetos thus established a small niche for themselves as lighting generators. The Belgian electrical engineer Floris Nollet (1794–1853) became particularly known for this type of arc lighting generator and founded the British-French company Société de l'Alliance to manufacture them. The French engineer Auguste de Méritens (1834–1898) developed magnetos further for this purpose. His innovation

3567-409: The capacity, quality, and cost of the network. Integrated Services Digital Network (ISDN) was launched in the 1980's, providing businesses and consumers with access to digital telephony services such as data, voice, video , and fax services. The development of digital data communications methods made it possible to digitize voice and transmit it as real-time data across computer networks and

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3654-413: The center proved too complex to engineer. Further, if the lines did penetrate the interior of the ring any e.m.f. produced would have opposed the e.m.f. from the outside of the ring because the wire on the inside was orientated in the opposite direction to that on the outside having turned through 180 degrees as it was wound. Eventually it was found to be more efficient to wrap a single loop of wire across

3741-470: The cradle base that housed the magneto crank and other parts. They were larger than the "candlestick" and more popular. Disadvantages of single-wire operation such as crosstalk and hum from nearby AC power wires had already led to the use of twisted pairs and, for long-distance telephones, four-wire circuits . Users at the beginning of the 20th century did not place long-distance calls from their own telephones but made an appointment and were connected with

3828-532: The desk set, obviating a separate ringer box. The rotary dial becoming commonplace in the 1930s in many areas enabled customer-dialed service, but some magneto systems remained even into the 1960s. After World War II, the telephone networks saw rapid expansion and more efficient telephone sets, such as the model 500 telephone in the United States, were developed that permitted larger local networks centered around central offices. A breakthrough new technology

3915-420: The device's functions, as well as enabling users to use spoken commands to interact with the internet. Typically alphanumeric text input is accomplished via an on-screen virtual keyboard, although some smartphones have a small physical keyboard. Smartphones offer the ability to access internet data through the cellular network and via wi-fi, and usually allow direct connectivity to other devices via Bluetooth or

4002-402: The earliest Strowger switch automatic exchanges had seven wires, one for the knife switch , one for each telegraph key , one for the bell, one for the push-button and two for speaking. Large wall telephones in the early 20th century usually incorporated the bell, and separate bell boxes for desk phones dwindled away in the middle of the century. Rural and other telephones that were not on

4089-457: The electrical device used the term. Perhaps the earliest use of the word for a communications system was the telephon created by Gottfried Huth in 1796. Huth proposed an alternative to the optical telegraph of Claude Chappe in which the operators in the signaling towers would shout to each other by means of what he called "speaking tubes", but would now be called giant megaphones . A communication device for sailing vessels, called telephone ,

4176-429: The exterior of the ring and simply not have any part of the loop pass through the interior. This also reduces construction complexity since one large winding spanning the width of the ring is able to take the place of two smaller windings on opposite sides of the ring. All modern armatures use this externally wrapped (drum) design, although the windings do not extend fully across the diameter; they are more akin to chords of

4263-524: The first digital cellular networks appearing in the early 1990s. Mobile phones require a SIM card to be inserted into the phone. The SIM card is a small PVC card containing a small integrated circuit which stores the user's international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers to the cellular network. Mobile phones generally incorporate an LCD or OLED display, with some types, such as smartphones, having touch screens. Since

4350-439: 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, virtually all piston engine aircraft are fitted with two magneto systems, each supplying power to one of two spark plugs in each cylinder. Magnetos were used for specialized isolated power systems such as arc lamp systems or lighthouses , for which their simplicity

4437-526: The ignition systems of spark-ignition piston engines. Magnetos are used in piston aircraft engines for their reliability and simplicity, often in pairs. Motor sport vehicles such as motorcycles and snowmobiles may use magnetos because they are lighter in weight than an ignition system relying on a battery. Small internal combustion engines used for lawn mowers, chain saws, portable pumps and similar applications use magnetos for economy and weight reduction. Magnetos are not used in highway motor vehicles that have

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4524-420: The interior of the ring cuts no flux and does not contribute to energy conversion in the machine. The winding requires twice the number of turns and twice the number of commutator bars as an equivalent drum-wound armature. The Gramme machine used a ring armature, with a series of armature coils , wound around a revolving ring of soft iron . The coils are connected in series, and the junction between each pair

4611-407: The interior windings of each small coil are minimally effective at producing power because they cut very few lines of force compared with the windings on the exterior of the ring. The interior windings are effectively dead wire and only add resistance to the circuit, lowering efficiency. Initial attempts to insert a stationary field coil within the center of the ring to help the lines penetrate into

4698-531: The issue still arise from time to time. Charles Bourseul , Antonio Meucci , Johann Philipp Reis , Alexander Graham Bell , and Elisha Gray , amongst others, have all been credited with the invention of the telephone. Alexander Graham Bell was the first to be awarded a patent for the electric telephone by the United States Patent and Trademark Office (USPTO) in March 1876. Before Bell's patent,

4785-402: The local communications system can be compromised. Gramme ring A Gramme machine , Gramme ring , Gramme magneto , or Gramme dynamo is an electrical generator that produces direct current , named for its Belgian inventor, Zénobe Gramme , and was built as either a dynamo or a magneto . It was the first generator to produce power on a commercial scale for industry. Inspired by

4872-412: The model 202 shows the direct connection of the transmitter to the line, while the receiver was inductively coupled. In local battery configurations, when the local loop was too long to provide sufficient current from the exchange, the transmitter was powered by a local battery and inductively coupled, while the receiver was included in the local loop. The coupling transformer and the ringer were mounted in

4959-405: The other and summing together. While the Gramme ring permitted a more steady power output, it suffered from a technical design inefficiency due to how magnetic lines of force pass through a ring armature. The field lines tend to concentrate within and follow the surface metal of the ring to the other side, with relatively few lines of force penetrating into the interior of the ring. Consequently,

5046-471: The other end, or the exchange operator , by whistling into the transmitter. Exchange operation soon resulted in telephones being equipped with a bell in a ringer box , first operated over a second wire, and later over the same wire, but with a condenser ( capacitor ) in series with the bell coil to allow the AC ringer signal through while still blocking DC (keeping the phone " on hook "). Telephones connected to

5133-409: The rotating shaft to the dynamo's rotating field coil. The output of the dynamo is then taken from the stator coils. This is 'inside-out' compared to the conventional dynamo, but avoids the need for brushgear. The invention of the self-exciting field by Varley , Siemens & Wheatstone removed the need for a magneto exciter. A small residual field in the iron armature of the field coils acted as

5220-525: The rotation of their rotors. Long air gaps create weak forces, resulting in low torque. A device called the St. Louis motor (still available from scientific supply houses), although not intended to, clearly demonstrates this great inefficiency, and seriously misleads students as to how real motors work. These early inefficient designs apparently were based on observing how magnets attracted ferromagnetic materials (such as iron and steel) from some distance away. It took

5307-636: The same (party) line . The development of modern rare-earth magnets makes the simple magneto alternator a more practical proposition as a power generator, as these permit a greatly increased field strength. As the magnets are compact and of light weight, they generally form the rotor, so the output windings can be placed on the stator, avoiding the need for brushgear. By the late 1980s, developments in magnetic materials such as samarium–cobalt , an early rare-earth type, let permanent magnet alternators be used in applications that require an extremely robust generator. In guided missiles , such generators can replace

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5394-432: The same magnetic field, the current forms a ring across the brush terminals. A two-pole, four-coil Gramme ring. The coils of A and A' sum together, as do the coils of B and B', producing two pulses of power 90° out of phase with each other. When coils A and A' are at maximum output, coils B and B' are at zero output. A three-pole, six-coil Gramme ring, and a graph of the combined three poles, each 120° out of phase from

5481-446: The sea air of a lighthouse, the commutator that had been used previously with dynamo generators was a continual source of trouble. The lighthouse keepers of the time, usually semi-retired sailors, were not mechanically or electrically skilled enough to maintain these more complex machines. The de Méritens magneto generator illustrated shows the 'ring wound' armature. As there is now only a single rotor disk, each horseshoe magnet comprises

5568-426: The service location to the emergency services when an emergency telephone number is called. A cordless telephone or portable telephone consists of a base station unit and one or more portable cordless handsets . The base station connects to a telephone line, or provides service by voice over IP (VOIP). The handset communicates with the base station via radio frequency signals. A handset's operational range

5655-453: The signals of a conventional analog telephone; an IP Phone , a dedicated standalone device; or a computer softphone application, utilizing the microphone and headset devices of a personal computer or smartphone. While traditional analog telephones are typically powered from the central office through the telephone line, digital telephones require a local power supply. Internet-based digital service also requires special provisions to provide

5742-510: The size of their keyboards. Typically, smartphones feature such tools as cameras, media players, web browsers, email clients, interactive maps, satellite navigation and a variety of sensors, such as a compass , accelerometers and GPS receivers . In addition to voice calls, smartphone users commonly communicate using a wide variety of messaging formats, including SMS, MMS, email, and various proprietary messaging services, such as iMessage and various social media platforms. In 2002, only 10% of

5829-458: The telephone transmitted sound in a way that was similar to the telegraph. This method used vibrations and circuits to send electrical pulses, but was missing key features. Bell found that this method produced a sound through intermittent currents, but in order for the telephone to work a fluctuating current reproduced sounds the best. The fluctuating currents became the basis for the working telephone, creating Bell's patent. That first patent by Bell

5916-781: The transmissions of diesel-electric locomotives . Magnetos have advantages of simplicity and reliability, but are limited in size owing to the magnetic flux available from their permanent magnets. The fixed excitation of a magneto made it difficult to control its terminal voltage or reactive power production when operating on a synchronized grid. This restricted their use for high-power applications. Power generation magnetos were limited to narrow fields, such as powering arc lamps or lighthouses, where their particular features of output stability or simple reliability were most valued. Small wind turbines , particularly self-build designs, are widely adopting magneto alternators for generation. The generators use rotating neodymium rare-earth magnets with

6003-613: The use of an electrical generator in electroplating , rather than batteries. A machine was built in 1844 and licensed to the use of the Elkington Works in Birmingham . Such electroplating expanded to become an important aspect of the Birmingham toy industry , the manufacture of buttons, buckles and similar small metal items. The surviving machine has an applied field from four horseshoe magnets with axial fields. The rotor has ten axial bobbins. Electroplating requires DC and so

6090-438: The user alternately listening and speaking (or rather, shouting) into the same hole. Sometimes the instruments were operated in pairs at each end, making conversation more convenient but also more expensive. At first, the benefits of a telephone exchange were not exploited. Instead, telephones were leased in pairs to a subscriber , who had to arrange for a telegraph contractor to construct a line between them, for example, between

6177-402: The usual AC magneto is unworkable. Woolrich's machine, unusually, has a commutator to rectify its output to DC. Most early dynamos were bipolar and so their output varied cyclically as the armature rotated past the two poles. To achieve an adequate output power, magneto generators used many more poles; usually sixteen, from eight horseshoe magnets arranged in a ring. As the flux available

6264-522: The voice at a distant location. The receiver and transmitter are usually built into a handset which is held up to the ear and mouth during conversation. The transmitter converts the sound waves to electrical signals which are sent through the telecommunications system to the receiving telephone, which converts the signals into audible sound in the receiver or sometimes a loudspeaker . Telephones permit transmission in both directions simultaneously. Most telephones also contain an alerting feature, such as

6351-406: The wind. The brake disk, with its attached rare-earth magnets, rotates to form the armature. A plywood disk carrying multiple axial coils is placed alongside this, with an iron armature ring behind it. In large sizes, from the 100 kW to MW range, the machines developed for modern wind turbines are termed permanent magnet synchronous generators . One popular and common use of magnetos of today

6438-456: The world's population used mobile phones and by 2005 that percentage had risen to 46%. By the end of 2009, there were a total of nearly 6 billion mobile and fixed-line telephone subscribers worldwide. This included 1.26 billion fixed-line subscribers and 4.6 billion mobile subscribers. A satellite telephone, or satphone, is a type of mobile phone that connects to other phones or the telephone network by radio link through satellites orbiting

6525-517: The years, many types of mobile phone, notably smartphones, require an operating system to run. Popular mobile phone operating systems in the past have included Symbian , Palm OS , BlackBerry OS and mobile phone versions of Windows . As of 2022, the most used operating systems are Google's Android and Apple's iOS . Before the era of smartphones, mobile phones were generally manufactured by companies specializing in telecommunications equipment, such as Nokia , Motorola , and Ericsson . Since

6612-461: Was an impedance matching transformer to make it compatible with the impedance of the line. The Edison patents kept the Bell monopoly viable into the 20th century, by which time the network was more important than the instrument. Early telephones were locally powered, using either a dynamic transmitter or by the powering of a transmitter with a local battery. One of the jobs of outside plant personnel

6699-445: Was an advantage. They have never been widely applied for the purposes of bulk electricity generation , for the same purposes or to the same extent as either dynamos or alternators. Only in a few specialised cases have they been used for power generation. Production of electric current from a moving magnetic field was demonstrated by Faraday in 1831. The first machines to produce electric current from magnetism used permanent magnets;

6786-436: Was introduced, packaged in three parts. The transmitter stood on a stand, known as a " candlestick " for its shape. When not in use, the receiver hung on a hook with a switch in it, known as a "switchhook". Previous telephones required the user to operate a separate switch to connect either the voice or the bell. With the new kind, the user was less likely to leave the phone "off the hook". In phones connected to magneto exchanges,

6873-539: Was invented by Captain John Taylor in 1844. This instrument used four air horns to communicate with vessels in foggy weather. Johann Philipp Reis used the term in reference to his invention, commonly known as the Reis telephone , in c. 1860. His device appears to be the first device based on the conversion of sound into electrical impulses. The term telephone was adopted into the vocabulary of many languages. It

6960-480: Was limited by the magnet metallurgy, the only option was to increase the field by using more magnets. As this was still an inadequate power, extra rotor disks were stacked axially , along the axle. This had the advantage that each rotor disk could at least share the flux of two expensive magnets. The machine illustrated here uses eight disks and nine rows of magnets: 72 magnets in all. The rotors first used were wound as sixteen axial bobbins, one per pole. Compared to

7047-499: Was the master patent of the telephone, from which other patents for electric telephone devices and features flowed. In 1876, shortly after Bell's patent application, Hungarian engineer Tivadar Puskás proposed the telephone switch, which allowed for the formation of telephone exchanges , and eventually networks. In the United Kingdom, the blower is used as a slang term for a telephone. The term came from navy slang for

7134-536: Was the first powerful electric motor useful as more than a toy or laboratory curiosity. Today some elements of this design forms the basis of nearly all DC electric motors. Gramme's use of multiple commutator contacts with multiple overlapped coils, and his innovation of using a ring armature, was an improvement on earlier dynamos and helped usher in development of large-scale electrical devices. Earlier designs of electric motors were notoriously inefficient because they had large, or very large, air gaps throughout much of

7221-426: 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 microphone ( transmitter ) to speak into and an earphone ( receiver ) which reproduces

7308-591: Was the introduction of Touch-Tone signaling using push-button telephones by American Telephone & Telegraph Company (AT&T) in 1963. The invention of the transistor in 1947 dramatically changed the technology used in telephone systems and in the long-distance transmission networks, over the next several decades. With the development of stored program control and MOS integrated circuits for electronic switching systems , and new transmission technologies such as pulse-code modulation (PCM), telephony gradually evolved towards digital telephony , which improved

7395-525: Was to replace the rotor coils previously wound on individual bobbins, with a 'ring wound' armature. These windings were placed on a segmented iron core, similar to a Gramme ring , so as to form a single continuous hoop. This gave a more even output current, which was still more advantageous for arc lamps. De Méritens is best remembered today for his production of magneto generators specifically for lighthouses. These were favoured for their simplicity and reliability, in particular their avoidance of commutators. In

7482-423: Was to visit each telephone periodically to inspect the battery. During the 20th century, telephones powered from the telephone exchange over the same wires that carried the voice signals became common. Early telephones used a single wire for the subscriber's line, with ground return used to complete the circuit (as used in telegraphs ). The earliest dynamic telephones also had only one port opening for sound, with

7569-491: Was used only to supply the field to the larger alternator. These are illustrated in Rankin Kennedy 's work Electrical Installations Kennedy himself developed a simpler version of this, intended for lighting use on ships, where a dynamo and magneto were assembled on the same shaft. Kennedy's innovation here was to avoid the need for brushgear at all. The current generated in the magneto is transmitted by wires attached to

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