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...)
These are
Good articles, which meet a core set of high editorial standards.
Image 1
The Revox B215 is a
cassette deck manufactured by
Studer from 1985 until around 1990. A professional version with different control layout and audio path electronics was manufactured concurrently as the Studer A721. A later improved version was marketed as the Revox B215S. Because it was expensive compared to other consumer models and had exceptionally good mechanical performance and durability, the B215 was used primarily by professional customers—radio stations, recording studios and real-time cassette duplicators.
The B215 used a proven, reliable four-motor
tape transport derived from the earlier B710 model. The B215 differed from the B710 and competing decks of the period in having an unusual, computer-like control panel and elaborate automation performed by three
Philipsmicrocontrollers. The deck was equipped with automatic tape calibration, microcontroller-assisted setting of recording levels, and
non-volatile memory. (Full article...)
Image 2
Row hammer (also written as rowhammer) is a computer security exploit that takes advantage of an unintended and undesirable side effect in
dynamic random-access memory (DRAM) in which
memory cells interact electrically between themselves by leaking their charges, possibly changing the contents of nearby
memory rows that were not
addressed in the original memory access. This circumvention of the isolation between DRAM memory cells results from the high cell density in modern DRAM, and can be triggered by specially crafted
memory access patterns that rapidly activate the same memory rows numerous times.
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...)
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...)
Image 5
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...)
Image 6
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...)
Image 7
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...)
Image 8
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...)
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...)
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...)
Image 11
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...)
Numerically controlled oscillators offer several advantages over other types of oscillators in terms of agility, accuracy, stability and reliability. NCOs are used in many communications systems including digital up/down converters used in 3G wireless and software radio systems, digital
phase-locked loops, radar systems, drivers for optical or acoustic transmissions, and multilevel
FSK/
PSK modulators/demodulators. (Full article...)
Image 13
Figure 1. Waveguide slotted line Slotted lines are used for
microwave measurements and consist of a movable probe inserted into a slot in a
transmission line. They are used in conjunction with a microwave power source and usually, in keeping with their low-cost application, a low cost
Schottky diode detector and
VSWR meter rather than an expensive
microwave power meter.
Slotted lines can measure
standing waves,
wavelength, and, with some calculation or plotting on
Smith charts, a number of other parameters including
reflection coefficient and
electrical impedance. A precision variable
attenuator is often incorporated in the test setup to improve accuracy. This is used to make level measurements, while the detector and VSWR meter are retained only to mark a reference point for the attenuator to be set to, thus eliminating entirely the detector and meter measurement errors. The parameter most commonly measured by a slotted line is SWR. This serves as a measure of the accuracy of the impedance match to the item under test. This is especially important for transmitting antennas and their feed lines; high
standing wave ratio on a radio or TV antenna can distort the signal, increase transmission line loss and potentially damage components in the transmission path, possibly even the transmitter. (Full article...)
Image 14
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...)
Image 15
Analogue
filters are a basic building block of
signal processing much used in
electronics. Amongst their many applications are the separation of an audio signal before application to
bass,
mid-range, and
tweeterloudspeakers; the combining and later separation of multiple telephone conversations onto a single channel; the selection of a chosen
radio station in a
radio receiver and rejection of others.
Passive linear electronic analogue filters are those filters which can be described with
linear differential equations (linear); they are composed of
capacitors,
inductors and, sometimes,
resistors (
passive) and are designed to operate on continuously varying
analogue signals. There are many
linear filters which are not analogue in implementation (
digital filter), and there are many
electronic filters which may not have a passive topology – both of which may have the same
transfer function of the filters described in this article. Analogue filters are most often used in wave filtering applications, that is, where it is required to pass particular frequency components and to reject others from analogue (
continuous-time) signals. (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.
An antenna or aerial is an arrangement of aerial
electrical conductors designed to
transmit or
receiveradio waves which is a class of
electromagnetic waves. In other words, antennas basically convert radio frequency electrical currents into electromagnetic waves and vice versa. Antennas are used in systems such as
radio and
television broadcasting, point-to-point radio communication,
radar, and
space exploration. Antennas usually work in air or outer space, but can also be operated under water or even through soil and rock at certain frequencies for short distances.
Physically, an antenna is an arrangement of
conductors that generate a radiating
electromagnetic field in response to an applied alternating voltage and the associated alternating
electric current, or can be placed in an electromagnetic field so that the field will
induce an alternating current in the antenna and a voltage between its terminals. Some antenna devices (parabola, horn antenna) just adapt the free space to another type of antenna.
... that the source material for
Curtis Roads's electronic composition nscor was realized at six studios for a period of five years?
... that in 2019, Chinese electronics company
Xiaomi posted a video of their third-quarterly financial report featuring a parody of the
anime song "Renai Circulation"?
Consumer showcase
The Tungsten series was
Palm, Inc.'s line of business-class
Palm OS-based
PDAs. With the purchase of the Palm name from
PalmSource, Palm has dropped the Tungsten name from newer offerings. As of 2006, only the Tungsten E2 continues to use the Tungsten name. Palm's other business-class model continuing the Tungsten line is the
TX.
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...)
These are
Good articles, which meet a core set of high editorial standards.
Image 1
The Revox B215 is a
cassette deck manufactured by
Studer from 1985 until around 1990. A professional version with different control layout and audio path electronics was manufactured concurrently as the Studer A721. A later improved version was marketed as the Revox B215S. Because it was expensive compared to other consumer models and had exceptionally good mechanical performance and durability, the B215 was used primarily by professional customers—radio stations, recording studios and real-time cassette duplicators.
The B215 used a proven, reliable four-motor
tape transport derived from the earlier B710 model. The B215 differed from the B710 and competing decks of the period in having an unusual, computer-like control panel and elaborate automation performed by three
Philipsmicrocontrollers. The deck was equipped with automatic tape calibration, microcontroller-assisted setting of recording levels, and
non-volatile memory. (Full article...)
Image 2
Row hammer (also written as rowhammer) is a computer security exploit that takes advantage of an unintended and undesirable side effect in
dynamic random-access memory (DRAM) in which
memory cells interact electrically between themselves by leaking their charges, possibly changing the contents of nearby
memory rows that were not
addressed in the original memory access. This circumvention of the isolation between DRAM memory cells results from the high cell density in modern DRAM, and can be triggered by specially crafted
memory access patterns that rapidly activate the same memory rows numerous times.
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...)
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...)
Image 5
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...)
Image 6
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...)
Image 7
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...)
Image 8
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...)
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...)
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...)
Image 11
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...)
Numerically controlled oscillators offer several advantages over other types of oscillators in terms of agility, accuracy, stability and reliability. NCOs are used in many communications systems including digital up/down converters used in 3G wireless and software radio systems, digital
phase-locked loops, radar systems, drivers for optical or acoustic transmissions, and multilevel
FSK/
PSK modulators/demodulators. (Full article...)
Image 13
Figure 1. Waveguide slotted line Slotted lines are used for
microwave measurements and consist of a movable probe inserted into a slot in a
transmission line. They are used in conjunction with a microwave power source and usually, in keeping with their low-cost application, a low cost
Schottky diode detector and
VSWR meter rather than an expensive
microwave power meter.
Slotted lines can measure
standing waves,
wavelength, and, with some calculation or plotting on
Smith charts, a number of other parameters including
reflection coefficient and
electrical impedance. A precision variable
attenuator is often incorporated in the test setup to improve accuracy. This is used to make level measurements, while the detector and VSWR meter are retained only to mark a reference point for the attenuator to be set to, thus eliminating entirely the detector and meter measurement errors. The parameter most commonly measured by a slotted line is SWR. This serves as a measure of the accuracy of the impedance match to the item under test. This is especially important for transmitting antennas and their feed lines; high
standing wave ratio on a radio or TV antenna can distort the signal, increase transmission line loss and potentially damage components in the transmission path, possibly even the transmitter. (Full article...)
Image 14
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...)
Image 15
Analogue
filters are a basic building block of
signal processing much used in
electronics. Amongst their many applications are the separation of an audio signal before application to
bass,
mid-range, and
tweeterloudspeakers; the combining and later separation of multiple telephone conversations onto a single channel; the selection of a chosen
radio station in a
radio receiver and rejection of others.
Passive linear electronic analogue filters are those filters which can be described with
linear differential equations (linear); they are composed of
capacitors,
inductors and, sometimes,
resistors (
passive) and are designed to operate on continuously varying
analogue signals. There are many
linear filters which are not analogue in implementation (
digital filter), and there are many
electronic filters which may not have a passive topology – both of which may have the same
transfer function of the filters described in this article. Analogue filters are most often used in wave filtering applications, that is, where it is required to pass particular frequency components and to reject others from analogue (
continuous-time) signals. (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.
An antenna or aerial is an arrangement of aerial
electrical conductors designed to
transmit or
receiveradio waves which is a class of
electromagnetic waves. In other words, antennas basically convert radio frequency electrical currents into electromagnetic waves and vice versa. Antennas are used in systems such as
radio and
television broadcasting, point-to-point radio communication,
radar, and
space exploration. Antennas usually work in air or outer space, but can also be operated under water or even through soil and rock at certain frequencies for short distances.
Physically, an antenna is an arrangement of
conductors that generate a radiating
electromagnetic field in response to an applied alternating voltage and the associated alternating
electric current, or can be placed in an electromagnetic field so that the field will
induce an alternating current in the antenna and a voltage between its terminals. Some antenna devices (parabola, horn antenna) just adapt the free space to another type of antenna.
... that the source material for
Curtis Roads's electronic composition nscor was realized at six studios for a period of five years?
... that in 2019, Chinese electronics company
Xiaomi posted a video of their third-quarterly financial report featuring a parody of the
anime song "Renai Circulation"?
Consumer showcase
The Tungsten series was
Palm, Inc.'s line of business-class
Palm OS-based
PDAs. With the purchase of the Palm name from
PalmSource, Palm has dropped the Tungsten name from newer offerings. As of 2006, only the Tungsten E2 continues to use the Tungsten name. Palm's other business-class model continuing the Tungsten line is the
TX.
