Electronic devices have hugely influenced the development of many aspects of modern society, such as telecommunications, entertainment, education, health care, industry, and security. The main driving force behind the advancement of electronics is the semiconductor industry, which in response to global demand continually produces ever-more sophisticated electronic devices and circuits. The semiconductor industry is one of the largest and most profitable sectors in the global economy, with annual revenues exceeding $481 billion in 2018. The electronics industry also encompasses other sectors that rely on electronic devices and systems, such as e-commerce, which generated over $29 trillion in online sales in 2017. (Full article...)
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Foster's reactance theorem is an important theorem in the fields of electrical network analysis and synthesis. The theorem states that the reactance of a passive, lossless two-terminal (one-port) network always strictly monotonically increases with frequency. It is easily seen that the reactances of inductors and capacitors individually increase with frequency and from that basis a proof for passive lossless networks generally can be constructed. The proof of the theorem was presented by Ronald Martin Foster in 1924, although the principle had been published earlier by Foster's colleagues at American Telephone & Telegraph.
The theorem can be extended to admittances and the encompassing concept of immittances. A consequence of Foster's theorem is that zeros and poles of the reactance must alternate with frequency. Foster used this property to develop two canonical forms for realising these networks. Foster's work was an important starting point for the development of network synthesis. (Full article...)
Filters are required to operate at many different frequencies, impedances and bandwidths. The utility of a prototype filter comes from the property that all these other filters can be derived from it by applying a scaling factor to the components of the prototype. The filter design need thus only be carried out once in full, with other filters being obtained by simply applying a scaling factor. (Full article...)
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The circuit topology of an electronic circuit is the form taken by the network of interconnections of the circuit components. Different specific values or ratings of the components are regarded as being the same topology. Topology is not concerned with the physical layout of components in a circuit, nor with their positions on a circuit diagram; similarly to the mathematical concept of topology, it is only concerned with what connections exist between the components. There may be numerous physical layouts and circuit diagrams that all amount to the same topology.
Strictly speaking, replacing a component with one of an entirely different type is still the same topology. In some contexts, however, these can loosely be described as different topologies. For instance, interchanging inductors and capacitors in a low-passfilter results in a high-pass filter. These might be described as high-pass and low-pass topologies even though the network topology is identical. A more correct term for these classes of object (that is, a network where the type of component is specified but not the absolute value) is prototype network. (Full article...)
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The Yamaha NS-10 studio monitor, identifiable by its horizontal lettering and distinctive white cone. The Yamaha NS-10 is a loudspeaker that became a standard nearfield studio monitor in the music industry among rock and pop recording engineers. Launched in 1978, the NS-10 started life as a bookshelf speaker destined for the domestic environment. It was poorly received but eventually became a valuable tool with which to mix rock recordings. The speaker has a characteristic white-coloured mid–bass drive unit.
Technically, it is known as a speaker that easily reveals poor quality in recordings. Recording engineers sought to dull its treble response by hanging tissue paper in front of it, resulting in what became known as the "tissue paper effect" – a type of comb filtering. The NS-10 has been used to monitor a large number of successful recordings by numerous artists, leading Gizmodo to refer to it as "the most important loudspeaker you never heard of". (Full article...)
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The Samsung Galaxy S III (unofficially known as the Samsung Galaxy S3) is an Androidsmartphone designed, developed, and marketed by Samsung Electronics. Launched in 2012, it had sold more than 80 million units overall, making it the most sold phone in the S series. It is the third smartphone in the Samsung Galaxy S series.
It is distinguished from its predecessor by its larger and higher-resolution screen, higher storage options, a larger battery, and a video camera with stereo audio recording for a spatial effect on headphones and external speakers. While the picture and video resolutions of the camera stayed the same, its launching speed and shutter lag improved. (Full article...)
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Staggered tuning is a technique used in the design of multi-stage tuned amplifiers whereby each stage is tuned to a slightly different frequency. In comparison to synchronous tuning (where each stage is tuned identically) it produces a wider bandwidth at the expense of reduced gain. It also produces a sharper transition from the passband to the stopband. Both staggered tuning and synchronous tuning circuits are easier to tune and manufacture than many other filter types.
The function of stagger-tuned circuits can be expressed as a rational function and hence they can be designed to any of the major filter responses such as Butterworth and Chebyshev. The poles of the circuit are easy to manipulate to achieve the desired response because of the amplifier buffering between stages. (Full article...)
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Late model (c.1998) LS3/5A from Spendor, one of the BBC licensees The LS3/5A (each element pronounced separately, without the stroke) is a small studio monitor loudspeaker originated by the BBC for use by outside broadcast vans to ensure quality of their broadcasts. The speaker concept set out transparent and natural sound as the goal, and the achievement of the result is widely acknowledged.
The BBC granted licences to a small number of British firms, who first manufactured the product in 1975. The product underwent a change in 1987 due to consistency issues in manufacturing, and again in around 2003 when original parts from KEF ran out. Upwards of 60,000 pairs of the speaker have been sold. Reviewers have recognised its enormous importance as a bookshelf design. (Full article...)
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A time-domain reflectometer; an instrument used to locate the position of faults on lines from the time taken for a reflected wave to return from the discontinuity. A signal travelling along an electrical transmission line will be partly, or wholly, reflected back in the opposite direction when the travelling signal encounters a discontinuity in the characteristic impedance of the line, or if the far end of the line is not terminated in its characteristic impedance. This can happen, for instance, if two lengths of dissimilar transmission lines are joined.
This article is about signal reflections on electrically conducting lines. Such lines are loosely referred to as copper lines, and indeed, in telecommunications are generally made from copper, but other metals are used, notably aluminium in power lines. Although this article is limited to describing reflections on conducting lines, this is essentially the same phenomenon as optical reflections in fibre-optic lines and microwave reflections in waveguides. (Full article...)
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Sinclair Scientific calculator photographed c. 1974
The Sinclair Scientificcalculator was a 12-function, pocket-sized scientific calculator introduced in 1974, dramatically undercutting in price other calculators available at the time. The Sinclair Scientific Programmable, released a year later, was advertised as the first budget programmable calculator.
Significant modifications to the algorithms used meant that a chipset intended for a four-function calculator was able to process scientific functions, but at the cost of reduced speed and accuracy. Compared to contemporary scientific calculators, some functions were slow to execute, and others had limited accuracy or gave the wrong answer, but the cost of the Sinclair was a fraction of the cost of competing calculators. (Full article...)
This approach is especially useful in the design of mechanical filters—these use mechanical devices to implement an electrical function. However, the technique can be used to solve purely mechanical problems, and can also be extended into other, unrelated, energy domains. Nowadays, analysis by analogy is a standard design tool wherever more than one energy domain is involved. It has the major advantage that the entire system can be represented in a unified, coherent way. Electrical analogies are particularly used by transducer designers, by their nature they cross energy domains, and in control systems, whose sensors and actuators will typically be domain-crossing transducers. A given system being represented by an electrical analogy may conceivably have no electrical parts at all. For this reason domain-neutral terminology is preferred when developing network diagrams for control systems. (Full article...)
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The Sinclair Sovereign was a high-end calculator introduced by Clive Sinclair's company Sinclair Radionics in 1976. It was an attempt to escape from the unprofitable low end of the market, and one of the last calculators Sinclair produced. Made with a case of pressed steel that a variety of finishes, it cost between £30 and £60 at a time when other calculators could be purchased for under £5. A number of factors meant that the Sovereign was not a commercial success, including the cost, high import levies on components, competition from cheaper calculators manufactured abroad, and the development of more power-efficient designs using liquid-crystal displays. Though it came with a five-year guarantee, issues such as short battery life limited its usefulness. The company moved on to producing computers soon afterwards.
The iPhone 6 and iPhone 6 Plus are smartphones that were designed, developed, and marketed by Apple Inc. They are the eighth generation of the iPhone, succeeding the iPhone 5, iPhone 5c and iPhone 5s, and were announced on September 9, 2014, and released on September 19, 2014. The iPhone 6 and iPhone 6 Plus jointly were themselves replaced as the flagship devices of the iPhone series by the iPhone 6s and iPhone 6s Plus on September 9, 2015. The iPhone 6 and 6 Plus include larger 4.7 and 5.5 inches (120 and 140 mm) displays, a faster processor, upgraded cameras, improved LTE and Wi-Fi connectivity and support for a near-field communications-based mobile payments offering.
The iPhone 6 and 6 Plus received positive reviews, with critics regarding their redesign, specifications, camera, and battery life as being improvements over previous iPhone models. However, aspects of the design of iPhone 6 were also criticized, including plastic strips on the rear of the device for its antenna that disrupted the otherwise metal exterior, and the screen resolution of the standard-sized iPhone 6 being lower than other devices in its class. The iPhone 6 sold extremely well, making it the best-selling iPhone model and the most successful smartphone to date. (Full article...)
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The ZenFone 6 is a 2019 Android-based smartphone that was manufactured, released, and marketed by Asus. It is the only release in Asus' sixth-generation ZenFone lineup and directly succeeds the ZenFone 5Z. Asus chairman Jonney Shih unveiled the ZenFone 6 on 16 May 2019 in Valencia, Spain, and was released in Spain the following day.
The ZenFone 6 has a larger 6.4-inch (160 mm) display, a faster processor, and upgraded cameras than the ZenFone 5Z. The ZenFone 6's flip-up camera module doubles as a front-facing camera. It is the first mobile device Asus released after restructuring its smartphone division in late 2018. The ZenFone 6 was released in the Indian market as the "Asus 6Z". (Full article...)
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An antimetric electrical network is an electrical network that exhibits anti-symmetrical electrical properties. The term is often encountered in filter theory, but it applies to general electrical network analysis. Antimetric is the diametrical opposite of symmetric; it does not merely mean "asymmetric" (i.e., "lacking symmetry"). It is possible for networks to be symmetric or antimetric in their electrical properties without being physically or topologically symmetric or antimetric. (Full article...)
Hans Christian Ørsted (August 14, 1777 – March 9, 1851) was a Danishphysicist and chemist, influenced by the thinking of Immanuel Kant. He is best known for discovering the relationship between electricity and magnetism known as electromagnetism. In April 1820 he noticed a compass needle deflected from magnetic north when the electric current from the battery he was using was switched on and off. This deflection convinced him that magnetic fields radiate from all sides of a live wire just as light and heat do. The CGSunit of magnetic induction (oersted) is named in honor of his contributions to the field of electromagnetism.
Joule's laws are a set of two laws concerning the heat produced by a current and the energy dependence of an ideal gas to that of pressure, volume, and temperature, respecetively. Joule's first law, also known as the Joule effect, is a physical law expressing the relationship between the heat generated by the current flowing through a conductor. The heating effect of conductors carrying currents is known as Joule heating, named for James Prescott Joule. It is expressed as:
Where Q is the heat generated by a constant current I flowing through a conductor of electrical resistanceR, for a timet.
Joule's second law states that the internal energy of an ideal gas is independent of its volume and pressure, depending only its temperature.
Roomba is a roboticvacuum cleaner made and sold by iRobot. It is marketed as a Robotic Floorvac. The Roomba was first released in 2002 with updates and new models released in 2003, 2004, 2005 and 2006. As of May 2006[update], over 2 million units have been sold, making it the most successful domestic robot so far. The unit is a disc, thirteen inches (34 cm) in diameter and less than four inches (9 cm) high. A large contact-sensing bumper is mounted on the front half of the unit, with an infrared sensor at its top front center.
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