Electronic devices include diodes, transistors and X-ray tubes.

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Electronics, the branch of science and technology concerned with the nature, uses, and manufacture of devices in which electrons flow through a gas, vacuum, or semiconductor. All electronic devices are electrical—that is, they use or produce electric energy. Electronic devices are unique in that the flow of electricity in them can be controlled by electrical rather than mechanical means. Examples of electronic devices include diodes, transistors, and X-ray tubes.

Electronics occupies a central place in day-to-day activities in the developed countries of the world. For example, electronic systems are essential to many major industries—such as banking, telecommunications, and transportation—as well as to the government and armed forces.

Electronic devices are fundamental parts of a vast assortment of products, from hearing aids and digital watches to industrial robots and aircraft navigational instruments. Electronic devices are used in the design, manufacture, sale, and repair of a wide variety of products—including electronic devices themselves. Many forms of entertainment are provided by such electronic products as television sets, stereo systems, and videotape recorders.

One of the most noteworthy characteristics of modern electronic devices is that they can be made very small. The branch of electronics concerned with the miniaturization of electronic devices is called microelectronics. Microelectronics has made possible the development of personal electronic computers and many other kinds of electronic products.

In terms of the number of persons employed and in the value of production, the manufacture and sale of electronic devices is one of the major industries of the United States, Japan, South Korea, Great Britain, and many other countries. Some companies specialize in producing electronic parts; others, in the assembly of these parts into finished products; and yet others, in the sale and repair of electronic products.

Learn about the history of electronics on the next page.