# 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

Gustav Robert Kirchhoff (March 12, 1824 – October 17, 1887) was a German physicist who contributed to the fundamental understanding of electrical circuits, spectroscopy, and the emission of black-body radiation by heated objects. He coined the term "black body" radiation in 1862, and two sets of independent concepts in both circuit theory and thermal emission are named "Kirchhoff's laws" after him. Kirchhoff formulated his circuit laws, which are now ubiquitous in electrical engineering, in 1845, while still a student. He proposed his law of thermal radiation in 1859, and gave a proof in 1861.

## Selected design

Credit: commons:User:FDominec
This list of electronic components is intended to make drawing of schematics simple, fast and very flexible.

## Selected image

Credit: lirumlar
Microchip dragon: art work made from microchips and other electronic parts as seen in South Korea's Expo 2005 pavilion.

## 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

Remotely operated underwater vehicles (ROVs) is the common accepted name for tethered underwater robots in the offshore industry. ROVs are unoccupied, highly maneuverable and operated by a person aboard a surface vessel. They are linked to the ship by a tether, a group of cables that carry electrical power, video and data signals back and forth between the operator and the vehicle. Most ROVs are equipped with at least a video camera and lights. Additional equipment may include sonars, magnetometers, a still camera, a manipulator or cutting arm, water samplers, and instruments that measure water clarity, light penetration and temperature.

## 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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