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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Image 1
The Nakamichi Dragon is an audio
cassette deck that was introduced by
Nakamichi in 1982 and marketed until 1994. The Dragon was the first Nakamichi model with bidirectional replay capability and the world's first production tape recorder with an automatic
azimuth correction system; this feature, which was invented by
Philips engineers and improved by Niro Nakamichi, continuously adjusts the azimuth of the
replay head to minimize apparent head skew and correctly reproduce the
treble signal present on the tape. The system allows the correct reproduction of mechanically skewed cassettes and recordings made on misaligned decks. Apart from the Dragon, similar systems have only been used in the Nakamichi TD-1200 car cassette player and the
Marantz SD-930 cassette deck.
At the time of its introduction, the Dragon had the lowest-ever
wow and flutter and the highest-ever
dynamic range, losing marginally to the former Nakamichi flagship the 1000ZXL in
frequency response. Competing models by
Sony,
Studer,
Tandberg and
TEAC that were introduced later in the 1980s sometimes surpassed the Dragon in mechanical quality and feature set but none could deliver the same mix of sound quality, flexibility and technological advancement. The Dragon, despite inherent issues with long-term reliability, remained the highest point of
compact cassette technology. (Full article...)
The image method of filter design determines the properties of filter sections by calculating the properties they would have in an infinite chain of identical sections. In this, the analysis parallels
transmission line theory on which it is based. Filters designed by this method are called image parameter filters, or just image filters. An important parameter of image filters is their
image impedance, the impedance of an infinite chain of identical sections. (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...)
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The JBL Paragon, measuring almost 9 feet (2.7 m) from left to right The JBL D44000 Paragon is a one-piece stereo loudspeaker created by
JBL that was introduced in 1957 and discontinued in 1983; its production run was the longest of any JBL speaker. At its launch, the Paragon was the most expensive domestic loudspeaker on the market.
Designed by
Arnold Wolf from a concept elaborated by
Richard Ranger, it is almost 9 feet (2.7 m) long and requires over a hundred-man hours of hand-finishing by a team of dedicated craftsmen. Resembling less a conventional loudspeaker than an elegant sideboard, it is a landmark product for the company that was sought after by the well-heeled and by celebrities. With an estimated total production of about 1,000 units, it is highly sought after by collectors to this day. (Full article...)
The actual impedance may vary quite considerably from the nominal figure with changes in frequency. In the case of cables and other
transmission lines, there is also variation along the length of the cable, if it is not properly terminated. (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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The first-generation iPad (/ˈaɪpæd/;
EYE-pad) (retrospectively referred to unofficially as the iPad 1 or original iPad) is a
tablet computer designed and marketed by
Apple Inc. as the first device in the
iPad lineup of tablet computers. The device features an
Apple A4SoC, a 9.7 in (250 mm) touchscreen display, and, on certain variants, the capability of accessing cellular networks. Using the
iOS operating system, the iPad can
play music, send and receive email and
browse the web. Other functions, which include the ability to play
games and access
references,
GPS navigation software and
social network services can be enabled by downloading
apps.
The device was announced and unveiled on January 27, 2010, by Apple founder
Steve Jobs at an Apple press event. On April 3, 2010, the Wi-Fi variant of the device was released in the United States, followed by the release of the "
Wi-Fi +
3G" variant on April 30. On May 28, 2010, it was released in Australia, Canada, France, Japan, Italy, Germany, Spain, Switzerland and the United Kingdom. (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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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 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 Sinclair Executive was the world's first "slimline"
pocket calculator, and the first to be produced by
Clive Sinclair's company
Sinclair Radionics. Introduced in 1972, the calculator was produced in at least two versions with different keyboard markings; a variant called the Sinclair Executive Memory was introduced in 1973.
Its small size was made possible by pulsing current to the
Texas Instruments TMS1802 "calculator on a chip"
integrated circuit, reducing the power consumption more than tenfold. The Executive was highly successful, making £1.8 million of profit for Sinclair and winning a
Design Council Award for Electronics. (Full article...)
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A Leslie speaker in a clear plastic cabinet The Leslie speaker is a combined
amplifier and
loudspeaker that projects the signal from an electric or electronic instrument and modifies the sound by rotating a baffle chamber ("drum") in front of the loudspeakers. A similar effect is provided by a rotating system of horns in front of the treble driver. It is most commonly associated with the
Hammond organ, though it was later used for the
electric guitar and other instruments. A typical Leslie speaker contains an amplifier, a treble horn and a bass speaker—though specific components depend upon the model. A musician controls the Leslie speaker by either an external switch or pedal that alternates between a slow and fast speed setting, known as "
chorale" and "
tremolo".
The speaker is named after its inventor,
Donald Leslie, who began working in the late 1930s to get a speaker for a Hammond organ that better emulated a
pipe or
theatre organ, and discovered that baffles rotating along the axis of the speaker cone gave the best sound effect. Hammond was not interested in marketing or selling the speakers, so Leslie sold them himself as an add-on, targeting other organs as well as Hammond. Leslie made the first speaker in 1941. The sound of the organ being played through his speaker received national radio exposure across the US, and it became a commercial and critical success. It soon became an essential tool for most jazz organists. In 1965, Leslie sold his business to
CBS who, in 1980, sold it to Hammond.
Suzuki Musical Instrument Corporation subsequently acquired the Hammond and Leslie brands. (Full article...)
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m-derived filters or m-type filters are a type of
electronic filter designed using the
image method. They were invented by
Otto Zobel in the early 1920s. This filter type was originally intended for use with telephone
multiplexing and was an improvement on the existing
constant k type filter. The main problem being addressed was the need to achieve a better match of the filter into the terminating impedances. In general, all filters designed by the image method fail to give an exact match, but the m-type filter is a big improvement with suitable choice of the parameter m. The m-type filter section has a further advantage in that there is a rapid transition from the
cut-off frequency of the
passband to a
pole of
attenuation just inside the
stopband. Despite these advantages, there is a drawback with m-type filters; at frequencies past the pole of attenuation, the response starts to rise again, and m-types have poor stopband rejection. For this reason, filters designed using m-type sections are often designed as
composite filters with a mixture of k-type and m-type sections and different values of m at different points to get the optimum performance from both types. (Full article...)
The iPhone 5s maintained almost the same external design as its predecessor, the iPhone 5, although the 5s received a new white/gold color scheme in addition to white/silver and space gray/black. The 5s has vastly upgraded internal hardware, however. It introduced the
A7 64-bit dual-core system-on-chip, the first
64-bit processor to be used on a smartphone, accompanied by the
M7 "motion co-processor". A redesigned home button with
Touch ID, a
fingerprint recognition system which can be used to unlock the phone and authenticate
App Store and
iTunes Store purchases, was also introduced. The camera was also updated with a larger
aperture and a dual-LED flash optimized for different
color temperatures. Earphones known as EarPods were included with the 5s, and Apple released accessories including a case and a dock. It had a 4-inch display, similar to the iPhone 5 and iPhone 5c. (Full article...)
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The Electro-Dynamic Light Company of New York was a lighting and electrical distribution company organized in 1878. The company held the patents for the first practical incandescent electric lamp and electrical distribution system of incandescent electric lighting. They also held a patent for an electric meter to measure the amount of electricity used. The inventions were those of
Albon Man and
William E. Sawyer. They gave the patent rights to the company, which they had formed with a group of businessmen. It was the first company in the world formally established to provided electric lighting and was the first company organized specifically to manufacture and sell
incandescent electric light bulbs.
Man, an attorney from New York City, supplied money for experimentation to Sawyer, an electrical engineer. This partnership developed into the Electro-Dynamic Light Company that brought in other investors that became partners. Sawyer devised a unique electrical distribution system where electrical power could be obtained anywhere in the city from an electrical generator with the turn of a switch to light up electric lamps to produce glowing light like a gas lamp. It was unique in that it produced this power without consumers having to maintain local galvanic batteries and at a fraction of the cost of producing the same lighting as from gas lamps. Other features of the system were that safety devices were built in to prevent the early destroying of the other electric lamps in the circuit should there be a power surge due to a lamp burning up early and leaving the distribution circuit. The patents for the Man and Sawyer system were in place before any other electrical companies had similar systems. (Full article...)
The term electrical engineering may or may not encompass
electronic engineering. Where a distinction is made, electrical engineering is considered to deal with the problems associated with large-scale electrical systems such as
power transmission and
motor control, whereas electronic engineering deals with the study of small-scale electronic systems including
computers and
integrated circuits.
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