Electronics began practically in 1946, with a digital electronic computer called ENIAC, built with valve circuits. However, the idea behind a digital computer can be traced back to Charles Babbage, who built a mechanical computing device.
That part of electrical science is dedicated to the study of phenomena associated with the motion of electron beams in vacuum and gases (American standard definition of electrical terms, 1941).
The definition of e. also included the various devices, circuits, and applications based on these phenomena and, in particular, vacuum and gas tubes and many of the circuit devices used in radio engineering and telephone transmission systems.
Since in all these cases the intensity of the electric currents and the power levels were far lower than those used in traditional electrical engineering, the term 'weak current technique' was also used as a synonym for e., As opposed to 'current technique. strong 'as a synonym for electrical engineering.
From 1940 onwards, the panorama of devices, applications, and physical phenomena of electronic interest themselves has increased so rapidly that the original definition has been completely inadequate.
The progress of the e. they can be classified into three categories: a) introduction and development of solid-state devices with consequent miniaturization of electronic components; b) development of devices and apparatuses at increasingly higher frequencies, up to microwaves and optical devices; c) extraordinary increase in the complexity of devices and possible applications.
Consequently, the identification of the e. with the weak current technique, if we also take into account the fact that there is a part of the e., called industrial electronics, which deals with a wide class of electronic devices for medium and high powers.
beginnings of electronics
With the discovery of the electron (J.J. Thomson, 1897), as an essential component of matter and 'quantum' of electricity, the first phase of the history of e.
properly said. In the same year, the first cathode ray tube was created by F. Braun, which is the progenitor of the display devices used in oscilloscopes, televisions, and computer terminals.
In the following years, the process of electron emission from heated metals (thermoelectric emission) was clarified and set in quantitative terms by O.W. Richardson. In 1902 J.A. Fleming created the vacuum diode, which is the fundamental component to effect the transformation of a bidirectional current into a unidirectional one.
A decisive step in the development of the e. it was in 1906, when L. De Forest succeeded in inserting a third grid-shaped electrode in the diode in order to control the flow of electrons between the two main electrodes, thus creating the triode. With this component it was possible to realize for the first time a device equipped with amplification, ie capable of obtaining an amplified copy of the electrical signal present at the input at the output.
The triode was followed by various electron tubes equipped with multiple electrodes. Electron tubes became essential components in the construction of telecommunications equipment and systems (long-distance telephony, radio communications, etc.) and in various other applications.
Further progress was made with the creation of the first bistable circuits, with which the field of digital electronics was opened and the possibility of storing information in electronic circuits was shown; these circuits represented the basis of the subsequent realizations of the first digital computers.
Before and during the Second World War, research in the field of e. they had as their objective the realization of electron tubes for high frequencies and, secondly, the replacement of electron tubes with solid-state devices. The first field of study gave rise, during the Second World War, to the realization of the magnetron which was the first electron tube to generate high-power electrical signals in the microwave field. This component, which was followed by a wide class of similar devices, allowed the invention and development of the radar and made thee of strategic interest in the context of the conflict.
The second research field allowed the realization of the transistor, by W. Shockley, J. Bardeen, and W.H. Brattain (1947). This component laid the foundations of solid-state electronics and produced a real revolution in e. itself, so much so that most of the circuits and devices made previously are outdated. The first transistor called pointed (because it was made by means of point contacts placed at close distance on a germanium plate) was subsequently surpassed by the junction transistor (1951), much more stable and reliable. This invention was followed, in a few years, by the introduction of an extensive variety of solid-state electronic devices (various types of diodes, photovoltaic components, particle detector diodes, thyristors, field-effect transistors, etc.).
Starting in the mid-1950s, the 'transistorization' of the applications of e. (the first transistor radio dates back to 1954, the first transistor computer to 1957). Subsequently, a new revolution of e. was accomplished with the construction of integrated circuits, the first example of which was made in the Texas Instruments laboratories in 1958. It was an inevitable consequence of the invention of the transistor, which made it possible to create an entire circuit inside a tiny plate of semiconductor material. The integration of electronic devices immediately appeared advantageous and such as to make most of the previous devices once again obsolete. The advantages achieved have been innumerable, from the possibility of miniaturization to the increased frequency of use, to the increase in reliability (i.e. the possibility of correct operation over long periods of time). Then there is the improvement of the operating speed of digital devices, up to obtaining switching times of the order of nanoseconds. Finally, another very important advantage concerns the strong reduction of manufacturing costs.
This allowed the development of a new part of the e., Known as microelectronics. The progress made subsequently mainly concerned the increasing complexity of integrated circuits, identifiable by the number of components that can be made on the same silicon plate (chip) and the improvement of the performance of the devices. Integrated circuits have been created that contain over one million transistors in the area of a few square millimeters (VLSI, very-large-scale integration). Among the most widespread integrated circuits are very high-density memories, which digitally store data up to several billion bits, and the so-called microcomputers, which make a computer complete with its main parts in a single chip. Other innovative electronic devices have concerned the applications of superconductivity and the Josephson effect. This effect makes it possible to create amplifiers for extremely low input signals and very high-speed logic circuits, with very low power consumption. Parallel to the development of integrated electronics, the foundations of optoelectronics were laid, based on the use of lasers, optical fibers, and a wide range of optical components. The development of such devices finds wide application in various fields, among which that of telecommunications.
The most important distinction that can be made is that between analog electronics and digital (or numerical) electronics, even if this tends to blur in the hardware design phases, as each digital circuit must be designed and tested on an analog basis, considering the evolution of electrical quantities continuously over time. This distinction is also overcome in some types of computers that use hybrid circuits, that is, containing an analog and a digital part, as occurs in the case of neural networks.
The. analog deals with circuits and devices in which the various signals can take on a continuous set of values. The study of analog electronic circuits is addressed by means of the methodologies of the theory of electrical networks.
It is a typical feature of the e. the consideration of active circuits, ie in which transistors are present. In the case of passive circuits, that is, containing only resistors, capacitors, and inductors, the terms electric circuit or electronic circuit are substantially equivalent. The. uses the methods of electromagnetism in all problems involving aspects of propagation of electromagnetic waves or very high-frequency circuits (microwaves or millimeter waves).
The. digital deals with circuits and devices in which the various signals can only assume a discrete set of values (typically two values). In this case, the e. borders on information technology, as the e digital processes signals that can be identified with logic variables. The various logic circuits, which can be made according to different techniques, are grouped into logic families which are distinguished on the basis of the technology used for the construction of the elementary cells (logic gates), the power consumption, and the switching speed.
The logic families are identified with abbreviations (TTL, NMOS, CMOS, etc.). From the point of view of information technology, the electronic devices and architectures used in the construction of computing equipment are indicated by the term hardware, as opposed to programming methodologies, known by the term software.
It is evident that the hardware is based on the type of technology adopted and that the modification of the hardware of a computer represents a radical change in the characteristics of the machine compared to a modification of the software.
Name introduced in the 1980s and established internationally in the 1990s, to indicate that part of the e.
which treats electronic components with non-low voltage and/or high operating current, and studies the diagrams, equipment, and systems that use them in order to convert electrical energy in order to power the loads in an optimal way in relation to their type of operation.
The name, sometimes used in contrast to signal electronics, highlights the characterizing aspect of the high level of converted power and also that the aforementioned equipment is used in the electricity distribution and use sector.
It is sometimes confused and superimposed with industrial electronics, which includes broader application sectors. However, a power level is not identified above which the e. of power.
The great diffusion of e. of power and the consequent introduction of the denomination took place following the realization and development of semiconductor devices, such as the thyristor (also called SCR), the GTO, the bipolar power transistors, the IGBTs, the power MOSFETs, etc. .; in almost all cases these devices are used in the saturation zone, or as controlled switches.
The most important application sectors include: variable speed drives in industry and for vehicle traction; power supplies and in particular static uninterruptible power supplies; large converters (rectifiers and inverters) for direct current electricity transmission systems.
From a scientific and technological point of view, the e. of power is now to be considered mature and autonomous at the level of both university teaching and research programs. The issues that most characterize e. of power, in addition to the analysis aspects similar to those of the e. traditional, concern the power flows and therefore the efficiency problems, the protections against voltage gradients and overcurrents, the cooling modes, and the problems of induced disturbances.
The electronics industry recorded massive increases in terms of turnover in the 1990s, a consequence of the ever-widening range of products and the significant progress in their characteristics. In fact, the use and dissemination of electronic techniques have assumed an increasingly important role in relation to other industrial sectors, and more generally in the economic progress of modern society; fundamental and exclusive is the contribution of e. in the fields of telecommunications, automation, and information technology.
Among the causes that have determined the strong expansion of the sector, in addition to technological advances and new components with increasingly advanced characteristics, the continuous decrease in the cost-performance ratio of products that use electronic components is of fundamental importance.
The use of highly concentrated integrated circuits, a fundamental aspect in the development of information technology, has rapidly extended to the telecommunications and automation sectors, now becoming widely associated with digital techniques.
To these sectors must be added those of electronic equipment for the office and for the home, instrumentation and measurement systems / "> measurement and control, electromedical instrumentation, and special equipment.
The main producers of electronic components worldwide are the USA, Japan, and South Korea. Europe is present with two important semiconductor companies: the French-Italian STMicroelectronics and the Dutch NXP (an independent company founded by Philips Semiconductor ).
As for the Italian electronics industry, dependence on foreign countries for the supply of active and passive components (especially the most valuable ones) is high.
Type of musical expression in which the composer creates sounds starting from their constituent elements and then manipulates them with the instruments of electroacoustics and sound recording.
The beginning of research on the new possibilities offered by the e. to musical creation came with the establishment, in Cologne in 1951, of the Studio für Elektronische Musik directed by H. Eimert.
He was then joined by several musicians such as K. Stockhausen, H. Pousseur, F. Evangelisti. In imitation of the Cologne study, similar centers were established in various countries: in Gravesano, in the Canton of Ticino, the UNESCO experimental study of electroacoustics was established in 1955, directed by H. Scherchen; in Milan in 1956 the studio of musical phonology was established, of which L. Berio and B. Maderna were the animators. Among the most important evolutions of the 1980s and 1990s, a significant role is played by the numerous applications of information technology to musical and musicological work.
The development of audio-digital technologies, in addition to allowing the close interaction between sound and visual media, which has given rise to the broad line of multimedia works, has helped to untie the performance of music and. from the mere reproduction of magnetic tape: more and more often the interpretation takes place to live, both as live electronics, and as the manipulation, in real-time, of the sound of traditional instruments.