# Portal:Electronics

## The Electronics portal

Surface-mount electronic components

Electronics comprises the physics, engineering, technology and applications that deal with the emission, flow and control of electrons in vacuum and matter. The identification of the electron in 1897, along with the invention of the vacuum tube, which could amplify and rectify small electrical signals, inaugurated the field of electronics and the electron age.

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.

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.

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

Joseph Henry (December 17, 1797 – May 13, 1878) was a Scottish-American scientist. During his lifetime, he was considered one of the greatest American scientists since Benjamin Franklin. While building electromagnets, he discovered the electromagnetic phenomenon of self-inductance. He also discovered mutual inductance independently of Faraday, though Faraday was the first to publish his results. His work on the electromagnetic relay was the basis of the electrical telegraph, jointly invented by Samuel Morse and Charles Wheatstone. The SI unit of inductance, the henry, is named after him.

## Selected design

Credit: User:Ilmari Karonen
A diagram of a Möbius resistor showing the current flow.

## 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

Roomba is a robotic vacuum 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, 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.

## Selected article

Inductance is a measure of the amount of magnetic flux produced for a given electric current. The term was coined by Oliver Heaviside in February 1886. The SI unit of inductance is the henry (symbol: H), in honour of Joseph Henry. The symbol L is used for inductance, possibly in honour of the physicist Heinrich Lenz.

The inductance has the following relationship:

${\displaystyle L={\frac {\Phi }{i}}}$

where; L is the inductance in henrys, i is the current in amperes, Φ is the magnetic flux in webers. Strictly speaking, the quantity just defined is called self-inductance, because the magnetic field is created solely by the conductor that carries the current.

When a conductor is coiled upon itself N number of times around the same axis (forming a solenoid), the current required to produce a given amount of flux is reduced by a factor of N compared to a single turn of wire. Thus, the inductance of a coil of wire of N turns is given by:

${\displaystyle L={\frac {\lambda }{i}}=N{\frac {\Phi }{i}}}$

where, ${\displaystyle \lambda }$ is the total 'flux linkage'.

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