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86-413: 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 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

172-470: A mass-production basis, they opened the door for more compact devices. The first integrated circuits were the hybrid integrated circuit invented by Jack Kilby at Texas Instruments in 1958 and the monolithic integrated circuit chip invented by Robert Noyce at Fairchild Semiconductor in 1959. The MOSFET (metal–oxide–semiconductor field-effect transistor, or MOS transistor) was invented by Mohamed Atalla and Dawon Kahng at BTL in 1959. It

258-807: A professional body or an international standards organization. These include the International Electrotechnical Commission (IEC), the National Society of Professional Engineers (NSPE), the Institute of Electrical and Electronics Engineers (IEEE) and the Institution of Engineering and Technology (IET, formerly the IEE). Electrical engineers work in a very wide range of industries and the skills required are likewise variable. These range from circuit theory to

344-441: 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 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

430-460: A DC machine, two sources of magnetic fluxes are present; 'armature flux' and 'main field flux'. The effect of armature flux on the main field flux is called "armature reaction". The armature reaction changes the distribution of the magnetic field, which affects the operation of the machine. The effects of the armature flux can be offset by adding a compensating winding to the main poles, or in some machines adding intermediate magnetic poles, connected in

516-439: 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

602-412: A clear distinction between magnetism and static electricity . He is credited with establishing the term "electricity". He also designed the versorium : a device that detects the presence of statically charged objects. In 1762 Swedish professor Johan Wilcke invented a device later named electrophorus that produced a static electric charge. By 1800 Alessandro Volta had developed the voltaic pile ,

688-408: A conducting coil. The armature must carry current , so it is always a conductor or a conductive coil, oriented normal to both the field and to the direction of motion, torque (rotating machine), or force (linear machine). The armature's role is twofold. The first is to carry current across the field, thus creating shaft torque in a rotating machine or force in a linear machine. The second role

774-526: A degree is usually four or five years and the completed degree may be designated as a Bachelor of Science in Electrical/Electronics Engineering Technology, Bachelor of Engineering , Bachelor of Science, Bachelor of Technology , or Bachelor of Applied Science , depending on the university. The bachelor's degree generally includes units covering physics , mathematics, computer science , project management , and

860-627: 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 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

946-415: A forerunner of the electric battery. In the 19th century, research into the subject started to intensify. Notable developments in this century include the work of Hans Christian Ørsted , who discovered in 1820 that an electric current produces a magnetic field that will deflect a compass needle; of William Sturgeon , who in 1825 invented the electromagnet ; of Joseph Henry and Edward Davy , who invented

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1032-643: A general electronic component. The most common microelectronic components are semiconductor transistors , although all main electronic components ( resistors , capacitors etc.) can be created at a microscopic level. Nanoelectronics is the further scaling of devices down to nanometer levels. Modern devices are already in the nanometer regime, with below 100 nm processing having been standard since around 2002. Microelectronic components are created by chemically fabricating wafers of semiconductors such as silicon (at higher frequencies, compound semiconductors like gallium arsenide and indium phosphide) to obtain

1118-399: A given rating of machine, a wave winding is more suitable for large currents and low voltages. Windings are held in slots in the rotor or armature covered by stator magnets. The exact distribution of the windings and selection of the number of slots per pole of the field greatly influences the design of the machine and its performance, affecting such factors as commutation in a DC machine or

1204-401: 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

1290-459: A huge number of specializations including hardware engineering, power electronics , electromagnetics and waves, microwave engineering , nanotechnology , electrochemistry , renewable energies, mechatronics/control, and electrical materials science. Electrical engineers typically hold a degree in electrical engineering, electronic or electrical and electronic engineering. Practicing engineers may have professional certification and be members of

1376-407: A large number—often millions—of tiny electrical components, mainly transistors , into a small chip around the size of a coin . This allowed for the powerful computers and other electronic devices we see today. Microelectronics engineering deals with the design and microfabrication of very small electronic circuit components for use in an integrated circuit or sometimes for use on their own as

1462-424: 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

1548-511: A path for ventilation and cooling in high power applications. In small armatures a solid drum is often used simply for ease of construction, since the core can be easily formed from a stack of stamped metal disks keyed to lock into a slot on the shaft. 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 AC even on DC machines, due to

1634-505: A profession in the later 19th century. Practitioners had created a global electric telegraph network, and the first professional electrical engineering institutions were founded in the UK and the US to support the new discipline. Francis Ronalds created an electric telegraph system in 1816 and documented his vision of how the world could be transformed by electricity. Over 50 years later, he joined

1720-782: 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 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

1806-415: 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

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1892-426: A variety of industries. Electronic engineering involves the design and testing of electronic circuits that use the properties of components such as resistors , capacitors , inductors , diodes , and transistors to achieve a particular functionality. The tuned circuit , which allows the user of a radio to filter out all but a single station, is just one example of such a circuit. Another example to research

1978-470: Is a pneumatic signal conditioner. Prior to the Second World War, the subject was commonly known as radio engineering and basically was restricted to aspects of communications and radar , commercial radio , and early television . Later, in post-war years, as consumer devices began to be developed, the field grew to include modern television, audio systems, computers, and microprocessors . In

2064-444: Is an engineering discipline that deals with the convergence of electrical and mechanical systems. Such combined systems are known as electromechanical systems and have widespread adoption. Examples include automated manufacturing systems , heating, ventilation and air-conditioning systems , and various subsystems of aircraft and automobiles . Electronic systems design is the subject within electrical engineering that deals with

2150-400: Is called cross magnetization of the armature. The effect of the armature field is to distort the generator field and shift the neutral plane. The neutral plane is the position where the armature windings are moving parallel to the magnetic flux lines, that is why an axis lying in this plane is called as magnetic neutral axis (MNA). This effect is known as armature reaction and is proportional to

2236-427: Is satisfactory in installations in which the generator operates under a fairly constant load. If the load varies to a marked degree, the neutral plane will shift proportionately, and the brushes will not be the correct position at all times. The brush-setting method is the most common means of correcting for armature reaction in small generators (those producing approximately 1,000 W or less). Larger generators require

2322-798: Is still important in the design of many control systems . DSP processor ICs are found in many types of modern electronic devices, such as digital television sets , radios, hi-fi audio equipment, mobile phones, multimedia players , camcorders and digital cameras, automobile control systems, noise cancelling headphones, digital spectrum analyzers , missile guidance systems, radar systems, and telematics systems. In such products, DSP may be responsible for noise reduction , speech recognition or synthesis , encoding or decoding digital media, wirelessly transmitting or receiving data, triangulating positions using GPS , and other kinds of image processing , video processing , audio processing , and speech processing . Instrumentation engineering deals with

2408-461: Is their power consumption as this is closely related to their signal strength . Typically, if the power of the transmitted signal is insufficient once the signal arrives at the receiver's antenna(s), the information contained in the signal will be corrupted by noise , specifically static. Control engineering focuses on the modeling of a diverse range of dynamic systems and the design of controllers that will cause these systems to behave in

2494-472: Is there in the armature conductors, the MNA coincides with GNA. The brushes of a generator must be set in the neutral plane; that is, they must contact segments of the commutator that are connected to armature coils having no induced emf. If the brushes were contacting commutator segments outside the neutral plane, they would short-circuit "live" coils and cause arcing and loss of power. Without armature reaction,

2580-401: Is to generate an electromotive force (EMF). In the armature, an electromotive force is created by the relative motion of the armature and the field. When the machine or motor is used as a motor, this EMF opposes the armature current, and the armature converts electrical power to mechanical power in the form of torque , and transfers it via the shaft. When the machine is used as a generator,

2666-567: Is very useful for energy transmission as well as for information transmission. These were also the first areas in which electrical engineering was developed. Today, electrical engineering has many subdisciplines, the most common of which are listed below. Although there are electrical engineers who focus exclusively on one of these subdisciplines, many deal with a combination of them. Sometimes, certain fields, such as electronic engineering and computer engineering , are considered disciplines in their own right. Power & Energy engineering deals with

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2752-792: The Z3 , the world's first fully functional and programmable computer using electromechanical parts. In 1943, Tommy Flowers designed and built the Colossus , the world's first fully functional, electronic, digital and programmable computer. In 1946, the ENIAC (Electronic Numerical Integrator and Computer) of John Presper Eckert and John Mauchly followed, beginning the computing era. The arithmetic performance of these machines allowed engineers to develop completely new technologies and achieve new objectives. In 1948, Claude Shannon published "A Mathematical Theory of Communication" which mathematically describes

2838-452: The commutator action (which periodically reverses current direction) or due to electronic commutation, as in brushless DC motors . The armature can be on either the rotor (rotating part) or the stator (stationary part), depending on the type of electric machine. 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

2924-548: The compression , error detection and error correction of digitally sampled signals. Signal processing is a very mathematically oriented and intensive area forming the core of digital signal processing and it is rapidly expanding with new applications in every field of electrical engineering such as communications, control, radar, audio engineering , broadcast engineering , power electronics, and biomedical engineering as many already existing analog systems are replaced with their digital counterparts. Analog signal processing

3010-658: The doubling of transistors on an IC chip every two years, predicted by Gordon Moore in 1965. Silicon-gate MOS technology was developed by Federico Faggin at Fairchild in 1968. Since then, the MOSFET has been the basic building block of modern electronics. The mass-production of silicon MOSFETs and MOS integrated circuit chips, along with continuous MOSFET scaling miniaturization at an exponential pace (as predicted by Moore's law ), has since led to revolutionary changes in technology, economy, culture and thinking. The Apollo program which culminated in landing astronauts on

3096-520: The electrical relay in 1835; of Georg Ohm , who in 1827 quantified the relationship between the electric current and potential difference in a conductor ; of Michael Faraday , the discoverer of electromagnetic induction in 1831; and of James Clerk Maxwell , who in 1873 published a unified theory of electricity and magnetism in his treatise Electricity and Magnetism . In 1782, Georges-Louis Le Sage developed and presented in Berlin probably

3182-452: The generation , transmission , and distribution of electricity as well as the design of a range of related devices. These include transformers , electric generators , electric motors , high voltage engineering, and power electronics . In many regions of the world, governments maintain an electrical network called a power grid that connects a variety of generators together with users of their energy. Users purchase electrical energy from

3268-448: The transmission of information across a communication channel such as a coax cable , optical fiber or free space . Transmissions across free space require information to be encoded in a carrier signal to shift the information to a carrier frequency suitable for transmission; this is known as modulation . Popular analog modulation techniques include amplitude modulation and frequency modulation . The choice of modulation affects

3354-429: The 1850s had shown the relationship of different forms of electromagnetic radiation including the possibility of invisible airborne waves (later called "radio waves"). In his classic physics experiments of 1888, Heinrich Hertz proved Maxwell's theory by transmitting radio waves with a spark-gap transmitter , and detected them by using simple electrical devices. Other physicists experimented with these new waves and in

3440-661: The Moon with Apollo 11 in 1969 was enabled by NASA 's adoption of advances in semiconductor electronic technology , including MOSFETs in the Interplanetary Monitoring Platform (IMP) and silicon integrated circuit chips in the Apollo Guidance Computer (AGC). The development of MOS integrated circuit technology in the 1960s led to the invention of the microprocessor in the early 1970s. The first single-chip microprocessor

3526-580: The Royal Academy of Natural Sciences and Arts of Barcelona. Salva's electrolyte telegraph system was very innovative though it was greatly influenced by and based upon two discoveries made in Europe in 1800—Alessandro Volta's electric battery for generating an electric current and William Nicholson and Anthony Carlyle's electrolysis of water. Electrical telegraphy may be considered the first example of electrical engineering. Electrical engineering became

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3612-558: The amplifier tube, called the triode . In 1920, Albert Hull developed the magnetron which would eventually lead to the development of the microwave oven in 1946 by Percy Spencer . In 1934, the British military began to make strides toward radar (which also uses the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station at Bawdsey in August 1936. In 1941, Konrad Zuse presented

3698-815: The applications of computer engineering. Photonics and optics deals with the generation, transmission, amplification, modulation, detection, and analysis of electromagnetic radiation . The application of optics deals with design of optical instruments such as lenses , microscopes , telescopes , and other equipment that uses the properties of electromagnetic radiation. Other prominent applications of optics include electro-optical sensors and measurement systems, lasers , fiber-optic communication systems, and optical disc systems (e.g. CD and DVD). Photonics builds heavily on optical technology, supplemented with modern developments such as optoelectronics (mostly involving semiconductors ), laser systems, optical amplifiers and novel materials (e.g. metamaterials ). Mechatronics

3784-885: The armature EMF drives the armature current, and the shaft's movement is converted to electrical power. In an induction generator , generated power is drawn from the stator . A growler is used to check the armature for short and open circuits and leakages to ground. The word armature was first used in its electrical sense, i.e. keeper of a magnet , in mid 19th century. The parts of an alternator or related equipment can be expressed in either mechanical terms or electrical terms. Although distinctly separate these two sets of terminology are frequently used interchangeably or in combinations that include one mechanical term and one electrical term. This may cause confusion when working with compound machines like brushless alternators, or in conversation among people who are accustomed to work with differently configured machinery. In most generators,

3870-405: The armature circuit. Armature reaction is essential in amplidyne rotating amplifiers. Armature reaction drop is the effect of a magnetic field on the distribution of the flux under main poles of a generator. Since an armature is wound with coils of wire, a magnetic field is set up in the armature whenever a current flows in the coils. This field is at right angles to the generator field and

3956-413: 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

4042-413: The cost and performance of a system and these two factors must be balanced carefully by the engineer. Once the transmission characteristics of a system are determined, telecommunication engineers design the transmitters and receivers needed for such systems. These two are sometimes combined to form a two-way communication device known as a transceiver . A key consideration in the design of transmitters

4128-411: The current flowing in the armature coils. The geometrical neutral axis (GNA) is the axis that bisects the angle between the centre line of adjacent poles. The magnetic neutral axis (MNA) is the axis drawn perpendicular to the mean direction of the flux passing through the centre of the armature. No e.m.f. is produced in the armature conductors along this axis because then they cut no flux. When no current

4214-519: The curvature of the Earth. Marconi later transmitted the wireless signals across the Atlantic between Poldhu, Cornwall , and St. John's, Newfoundland , a distance of 2,100 miles (3,400 km). Millimetre wave communication was first investigated by Jagadish Chandra Bose during 1894–1896, when he reached an extremely high frequency of up to 60   GHz in his experiments. He also introduced

4300-500: The design of devices to measure physical quantities such as pressure , flow , and temperature. The design of such instruments requires a good understanding of physics that often extends beyond electromagnetic theory . For example, flight instruments measure variables such as wind speed and altitude to enable pilots the control of aircraft analytically. Similarly, thermocouples use the Peltier-Seebeck effect to measure

4386-561: The design of new hardware . Computer engineers may also work on a system's software. However, the design of complex software systems is often the domain of software engineering, which is usually considered a separate discipline. Desktop computers represent a tiny fraction of the devices a computer engineer might work on, as computer-like architectures are now found in a range of embedded devices including video game consoles and DVD players . Computer engineers are involved in many hardware and software aspects of computing. Robots are one of

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4472-577: The desired manner. To implement such controllers, electronics control engineers may use electronic circuits , digital signal processors , microcontrollers , and programmable logic controllers (PLCs). Control engineering has a wide range of applications from the flight and propulsion systems of commercial airliners to the cruise control present in many modern automobiles . It also plays an important role in industrial automation . Control engineers often use feedback when designing control systems . For example, in an automobile with cruise control

4558-420: The desired transport of electronic charge and control of current. The field of microelectronics involves a significant amount of chemistry and material science and requires the electronic engineer working in the field to have a very good working knowledge of the effects of quantum mechanics . Signal processing deals with the analysis and manipulation of signals . Signals can be either analog , in which case

4644-429: 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

4730-462: The field magnet is rotating, and is part of the rotor , while the armature is stationary, and is part of the stator . Both motors and generators can be built either with a stationary armature and a rotating field or a rotating armature and a stationary field. The pole piece of a permanent magnet or electromagnet and the moving, iron part of a solenoid , especially if the latter acts as a switch or relay , may also be referred to as armatures. In

4816-570: The first Department of Electrical Engineering in the United States. In the same year, University College London founded the first chair of electrical engineering in Great Britain. Professor Mendell P. Weinbach at University of Missouri established the electrical engineering department in 1886. Afterwards, universities and institutes of technology gradually started to offer electrical engineering programs to their students all over

4902-583: The future it is hoped the devices will help build tiny implantable medical devices and improve optical communication . In aerospace engineering and robotics , an example is the most recent electric propulsion and ion propulsion. Electrical engineers typically possess an academic degree with a major in electrical engineering, electronics engineering , electrical engineering technology , or electrical and electronic engineering. The same fundamental principles are taught in all programs, though emphasis may vary according to title. The length of study for such

4988-429: The generator design. These are two principal methods by which the effect of armature reaction is overcome. The first method is to shift the position of the brushes so that they are in the neutral plane when the generator is producing its normal load current. in the other method, special field poles, called interpoles, are installed in the generator to counteract the effect of armature reaction. The brush-setting method

5074-533: The grid, avoiding the costly exercise of having to generate their own. Power engineers may work on the design and maintenance of the power grid as well as the power systems that connect to it. Such systems are called on-grid power systems and may supply the grid with additional power, draw power from the grid, or do both. Power engineers may also work on systems that do not connect to the grid, called off-grid power systems, which in some cases are preferable to on-grid systems. Telecommunications engineering focuses on

5160-407: 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

5246-458: The international standardization of the units volt , ampere , coulomb , ohm , farad , and henry . This was achieved at an international conference in Chicago in 1893. The publication of these standards formed the basis of future advances in standardization in various industries, and in many countries, the definitions were immediately recognized in relevant legislation. During these years,

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5332-556: The latter half of the 19th century after the commercialization of the electric telegraph , the telephone, and electrical power generation, distribution, and use. Electrical engineering is divided into a wide range of different fields, including computer engineering , systems engineering , power engineering , telecommunications , radio-frequency engineering , signal processing , instrumentation , photovoltaic cells , electronics , and optics and photonics . Many of these disciplines overlap with other engineering branches, spanning

5418-412: The magnetic neutral axis (MNA) would coincide with geometrical neutral axis (GNA). Armature reaction causes the neutral plane to shift in the direction of rotation, and if the brushes are in the neutral plane at no load, that is, when no armature current is flowing, they will not be in the neutral plane when armature current is flowing. For this reason it is desirable to incorporate a corrective system into

5504-399: The management skills of a project manager . The tools and equipment that an individual engineer may need are similarly variable, ranging from a simple voltmeter to sophisticated design and manufacturing software. Electricity has been a subject of scientific interest since at least the early 17th century. William Gilbert was a prominent early electrical scientist, and was the first to draw

5590-446: The mid-to-late 1950s, the term radio engineering gradually gave way to the name electronic engineering . Before the invention of the integrated circuit in 1959, electronic circuits were constructed from discrete components that could be manipulated by humans. These discrete circuits consumed much space and power and were limited in speed, although they are still common in some applications. By contrast, integrated circuits packed

5676-511: The multi-disciplinary design issues of complex electrical and mechanical systems. The term mechatronics is typically used to refer to macroscopic systems but futurists have predicted the emergence of very small electromechanical devices. Already, such small devices, known as microelectromechanical systems (MEMS), are used in automobiles to tell airbags when to deploy, in digital projectors to create sharper images, and in inkjet printers to create nozzles for high definition printing. In

5762-519: The new Society of Telegraph Engineers (soon to be renamed the Institution of Electrical Engineers ) where he was regarded by other members as the first of their cohort. By the end of the 19th century, the world had been forever changed by the rapid communication made possible by the engineering development of land-lines, submarine cables , and, from about 1890, wireless telegraphy . Practical applications and advances in such fields created an increasing need for standardized units of measure . They led to

5848-404: 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,

5934-525: The passage of information with uncertainty ( electrical noise ). The first working transistor was a point-contact transistor invented by John Bardeen and Walter Houser Brattain while working under William Shockley at the Bell Telephone Laboratories (BTL) in 1947. They then invented the bipolar junction transistor in 1948. While early junction transistors were relatively bulky devices that were difficult to manufacture on

6020-401: The process developed devices for transmitting and detecting them. In 1895, Guglielmo Marconi began work on a way to adapt the known methods of transmitting and detecting these "Hertzian waves" into a purpose-built commercial wireless telegraphic system. Early on, he sent wireless signals over a distance of one and a half miles. In December 1901, he sent wireless waves that were not affected by

6106-430: 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

6192-425: The signal varies continuously according to the information, or digital , in which case the signal varies according to a series of discrete values representing the information. For analog signals, signal processing may involve the amplification and filtering of audio signals for audio equipment or the modulation and demodulation of signals for telecommunications. For digital signals, signal processing may involve

6278-411: The study of electricity was largely considered to be a subfield of physics since early electrical technology was considered electromechanical in nature. The Technische Universität Darmstadt founded the world's first department of electrical engineering in 1882 and introduced the first-degree course in electrical engineering in 1883. The first electrical engineering degree program in the United States

6364-444: The temperature difference between two points. Often instrumentation is not used by itself, but instead as the sensors of larger electrical systems. For example, a thermocouple might be used to help ensure a furnace's temperature remains constant. For this reason, instrumentation engineering is often viewed as the counterpart of control. Computer engineering deals with the design of computers and computer systems . This may involve

6450-412: The terminals of a Gramme machine to another dynamo which was producing electricity, and its shaft began to spin. The Gramme machine 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

6536-478: The theoretical basis of alternating current engineering. The spread in the use of AC set off in the United States what has been called the war of the currents between a George Westinghouse backed AC system and a Thomas Edison backed DC power system, with AC being adopted as the overall standard. During the development of radio , many scientists and inventors contributed to radio technology and electronics. The mathematical work of James Clerk Maxwell during

6622-424: The use of semiconductor junctions to detect radio waves, when he patented the radio crystal detector in 1901. In 1897, Karl Ferdinand Braun introduced the cathode-ray tube as part of an oscilloscope , a crucial enabling technology for electronic television . John Fleming invented the first radio tube, the diode , in 1904. Two years later, Robert von Lieben and Lee De Forest independently developed

6708-557: The use of transformers , developed rapidly in the 1880s and 1890s with transformer designs by Károly Zipernowsky , Ottó Bláthy and Miksa Déri (later called ZBD transformers), Lucien Gaulard , John Dixon Gibbs and William Stanley Jr. Practical AC motor designs including induction motors were independently invented by Galileo Ferraris and Nikola Tesla and further developed into a practical three-phase form by Mikhail Dolivo-Dobrovolsky and Charles Eugene Lancelot Brown . Charles Steinmetz and Oliver Heaviside contributed to

6794-412: The use of interpoles. Coils of the winding are distributed over the entire surface of the air gap, which may be the rotor or the stator of the machine. In a "lap" winding, there are as many current paths between the brush (or line) connections as there are poles in the field winding. In a "wave" winding, there are only two paths, and there are as many coils in series as half the number of poles. So, for

6880-485: The vehicle's speed is continuously monitored and fed back to the system which adjusts the motor's power output accordingly. Where there is regular feedback, control theory can be used to determine how the system responds to such feedback. Control engineers also work in robotics to design autonomous systems using control algorithms which interpret sensory feedback to control actuators that move robots such as autonomous vehicles , autonomous drones and others used in

6966-540: The waveform of an AC machine. Armature wiring is made from copper or aluminum . Copper armature wiring enhances electrical efficiencies due to its higher electrical conductivity . Aluminum armature wiring is lighter and less expensive than copper. Electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems that use electricity , electronics , and electromagnetism . It emerged as an identifiable occupation in

7052-414: The world's first form of electric telegraphy , using 24 different wires, one for each letter of the alphabet. This telegraph connected two rooms. It was an electrostatic telegraph that moved gold leaf through electrical conduction. In 1795, Francisco Salva Campillo proposed an electrostatic telegraph system. Between 1803 and 1804, he worked on electrical telegraphy, and in 1804, he presented his report at

7138-560: The world. During these decades the use of electrical engineering increased dramatically. In 1882, Thomas Edison switched on the world's first large-scale electric power network that provided 110 volts— direct current (DC)—to 59 customers on Manhattan Island in New York City. In 1884, Sir Charles Parsons invented the steam turbine allowing for more efficient electric power generation. Alternating current , with its ability to transmit power more efficiently over long distances via

7224-489: Was started at Massachusetts Institute of Technology (MIT) in the physics department under Professor Charles Cross, though it was Cornell University to produce the world's first electrical engineering graduates in 1885. The first course in electrical engineering was taught in 1883 in Cornell's Sibley College of Mechanical Engineering and Mechanic Arts . In about 1885, Cornell President Andrew Dickson White established

7310-458: Was the Intel 4004 , released in 1971. The Intel 4004 was designed and realized by Federico Faggin at Intel with his silicon-gate MOS technology, along with Intel's Marcian Hoff and Stanley Mazor and Busicom's Masatoshi Shima. The microprocessor led to the development of microcomputers and personal computers, and the microcomputer revolution . One of the properties of electricity is that it

7396-474: Was the first truly compact transistor that could be miniaturised and mass-produced for a wide range of uses. It revolutionized the electronics industry , becoming the most widely used electronic device in the world. The MOSFET made it possible to build high-density integrated circuit chips. The earliest experimental MOS IC chip to be fabricated was built by Fred Heiman and Steven Hofstein at RCA Laboratories in 1962. MOS technology enabled Moore's law ,

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