Electronics

The evolution of electronic technology is sometimes called a revolution. We have seen a steady quantitative evolution: smaller and smaller electronic components performing increasingly complex electronic functions at higher speeds.

Electronics began with the development of the transistor. Before the invention of the transistor in 1948 its function in an electronic circuit could be performed only by a vacuum tube. Tubes came in so many shapes and sizes and performed so many functions that in 1948 it seemed impossible to think that the transistor would be able to compete except in limited applications.

The first transistors had no striking advantage in size over the smallest tubes and they were more costly. The one great advantage the transistor had over the best vacuum tubes was exceedingly low power consumption. Besides, they promised greater reliability and longer life. However, it took years to demonstrate other transistor advantages.

Early transistors, being a size of a pea, were actually enormous and very slow. They could respond at a rate of a few million times a second; this was fast enough to serve in radio and hearing-aid circuits but far below the speed needed for high-speed computers or for microwave communication systems.

It is known that the speed of response depends primarily on the size of the transistor: the smaller the transistor, the faster it is. A microelectronic technology has made transistors and other circuit elements almost invisible to unaided eye.

It may be helpful if we say a few words about four of the principal devices found in electronic circuits: resistors, capacitors, diodes and transistors. Each device has a particular role in controlling the flow of electrons so that the completed circuit performs a desired function, such as amplification, oscillation, AC to DC conversion, frequency selection and so on. An assembly of circuits forms an electronic system, for example, the electronic system of a home radio or television set, or the guidance system of a rocket. The great percentage of today’s electronic systems is still put together in the traditional fashion – the assembly of individual components into circuits or subsystems that perform a given function.

Check your knowledge of the following terms.

Electronic circuit, vacuum tube, resistor, capacitor, transistor, frequency selection, diode, amplification, guidance system, oscillation, alternating current, microwave, direct current, conversion.

Дата добавления: 2015-07-18