Vacuum tube

In electronics, a vacuum tube (American English) or (thermionic) valve (British English) is a device generally used to amplify, or otherwise modify, a signal. Once used in most electronic devices, vacuum tubes are now used only in specialized applications. For most purposes, the vacuum tube has been replaced by the much smaller and less expensive transistor, either as a discrete device or in an integrated circuit. At the start of the 21st century there has been renewed interest in the vacuum tube, this time in the form of the Field-emitter microtube.

Applications

Tubes were ubiquitous in the early generations of electronic devices, such as radios, televisions, and early computers such as the Colossus which used 2000 tubes, the ENIAC which used nearly 18,000 tubes, and the IBM 700 series. Unlike transistors, vacuum tubes are inherently immune to the electromagnetic pulse effect of nuclear explosions. This property kept them in use for military applications long after transistors had replaced them elsewhere. Vacuum tubes are still used for very high-powered applications such as microwave ovens, industrial radio-frequency heating, and power amplification for broadcasting.

Related Topics:
Radio - Television - Computer - Colossus - ENIAC - IBM 700 series - Electromagnetic pulse - Nuclear explosion - Military - Microwave oven

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Tubes are also considered by many people in the audiophile, professional audio, and musician communities to have superior audio characteristics over transistor electronics. There are many companies who still make specialized audio hardware utilizing tube technology. Tubes' characteristic sound when overloaded is widely used in electric guitar amplification, and has defined the sound of some genres of music, including classic rock and rhythm and blues.

Related Topics:
Audiophile - Transistor - Electric guitar - Amplification

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