# Portal:Electronics

## The Electronics Portal

Modern surface-mount electronic components on a printed circuit board, with a large integrated circuit at the top.

The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification and rectification, which distinguishes it from classical electrical engineering, which only uses passive effects such as resistance, capacitance and inductance to control electric current flow.

Electronics has hugely influenced the development of modern society. The central driving force behind the entire electronics industry is the semiconductor industry sector, which has annual sales of over $481 billion as of 2018. The largest industry sector is e-commerce, which generated over$29 trillion in 2017. (Full article...)

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## Selected biography

Nikola Tesla (10 July 1856 - 7 January 1943) was an inventor, electrical and mechanical engineer known for his patents and theoretical work that contributed to modern alternating current electric power (AC) systems, including the polyphase power distribution systems and the AC induction motor. His contribution was recognized and the derived SI unit measuring magnetic flux density or magnetic induction (commonly known as the magnetic field ${\displaystyle B\,}$), the tesla, was named in his honor.

## Selected article

Capacitance is a measure of the amount of electric charge stored (or separated) for a given electric potential. The capacitance of the majority of capacitors used in electronic circuits is several orders of magnitude smaller than the farad. The energy (measured in joules) stored in a capacitor is equal to the work done to charge it.

${\displaystyle C={\frac {Q}{V}}}$

In a capacitor, there are two conducting electrodes which are insulated from one another. The charge on the electrodes is +Q and -Q, and V represents the potential difference between the electrodes. The SI unit of capacitance is the farad; 1 farad = 1 coulomb per volt.

${\displaystyle C=\epsilon {\frac {A}{d}}}$

The capacitance can be calculated if the geometry of the conductors and the dielectric properties of the insulator between the conductors are known, such as above, where; C is the capacitance in farads, ε is the permittivity of the insulator used (or ε0 for a vacuum), A is the area of each plane electrode in square metres, d is the separation between the electrodes in metres. The equation is a good approximation if d is small compared to the other dimensions of the electrodes.

## Consumer showcase

Columbia is a supercomputer built by Silicon Graphics for NASA. The supercomputer was installed at the NASA Advanced Supercomputing facility in 2004. According to the TOP500 list, it is currently the eighth fastest computer in the world running at 51.87 teraflops, or 51.87 trillion floating point calculations per second. It is composed of twenty SGI Altix 3000 nodes each of which have 512 Intel Itanium 2 processors bringing the total number of processors to 10,240. It was named in honour of the crew of the Space Shuttle Columbia.

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