# Portal:Electronics

## The Electronicsportal

Surface-mount electronic components

Electronics is the discipline dealing with the development and application of devices and systems involving the flow of electrons in a vacuum, in gaseous media, and in semiconductors. Electronics deals with electrical circuits that involve active electrical components such as vacuum tubes, transistors, diodes, integrated circuits, optoelectronics, and sensors, associated passive electrical components, and interconnection technologies. Commonly, electronic devices contain circuitry consisting primarily or exclusively of active semiconductors supplemented with passive elements; such a circuit is described as an electronic circuit.

Electronics is considered to be a branch of physics and electrical engineering.

The nonlinear behaviour of active components and their ability to control electron flows makes amplification of weak signals possible. Electronics is widely used in information processing, telecommunication, and signal processing. The ability of electronic devices to act as switches makes digital information processing possible. Interconnection technologies such as circuit boards, electronics packaging technology, and other varied forms of communication infrastructure complete circuit functionality and transform the mixed components into a regular working system.

Electrical and electromechanical science and technology deals with the generation, distribution, switching, storage, and conversion of electrical energy to and from other energy forms (using wires, motors, generators, batteries, switches, relays, transformers, resistors, and other passive components). This distinction started around 1906 with the invention by Lee De Forest of the triode, which made electrical amplification of weak radio signals and audio signals possible with a non-mechanical device. Until 1950 this field was called "radio technology" because its principal application was the design and theory of radio transmitters, receivers, and vacuum tubes.

Today, most electronic devices use semiconductor components to perform electron control. The study of semiconductor devices and related technology is considered a branch of solid-state physics, whereas the design and construction of electronic circuits to solve practical problems come under electronics engineering. This article focuses on engineering aspects of electronics.

## Selected biography

Heinrich Rudolf Hertz (February 22, 1857 - January 1, 1894) was the German physicist and mechanician for whom the hertz, an SI unit, is named. In 1888, he was the first to demonstrate the existence of electromagnetic radiation by building an apparatus to produce UHF radio waves. Hertz helped establish the photoelectric effect when he noticed that a charged object loses its charge more readily when illuminated by ultraviolet light. The Hertzian cone was first described by Hertz as a type of wave-front propagation through various media. His experiments help expand the field of electromagnetism transmission and his apparatus was developed further by others in the history of radio.

## Selected image

Credit: User:Fastfission
MRI sections through the Z-axis in a normal human adult.

## News

August 14, 2014

512K Day arrives, surpassing some routers capacity, breaking the internet. More...

November 19, 2008

The European Organization for Nuclear Research (CERN) said that repairing the Large Hadron Collider (LHC) will cost up to 16.6 million or US\$21 million. More...

April 30, 2008

HP Labs announces the creation of a Memristor, the fourth basic element of electronic circuits with the Resistor, Capacitor, and Inductor.

December 4, 2007

On the third day of the 2007 Taipei IT Month in Taiwan yesterday, notebook computers and desktop computers built with AMD's Phenom processor and Intel Penryn processor openly battled for the consumer-market after each company launched their quad core processors. More...

February 27, 2007

The new South Pole Telescope has recently collected its first light in a long-term project to learn about the nature of dark energy. More...

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## Consumer showcase

The iMac is a desktop computer designed and built by Apple Inc. It has been a cornerstone of Apple's Macintosh line of personal computers since its introduction in 1998, and has evolved through three distinct forms, all adhering to an "all-in-one" design ethos. The machine enjoys a relatively high profile in popular culture due to its distinctive aesthetics and Apple's successful marketing. The new 24" Core 2 Duo iMacs received CNET's "Must-have desktop" in their Top 10 Holiday Gift Picks.

## Selected article

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:

${\displaystyle Q=I^{2}\cdot R\cdot t}$

Where Q is the heat generated by a constant current I flowing through a conductor of electrical resistance R, for a time t.

Joule's second law states that the internal energy of an ideal gas is independent of its volume and pressure, depending only its temperature.

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