The electronics is a major field of electrical engineering . It is the science of controlling electrical current through electronic circuits , i.e. circuits in which at least one component works due to vacuum or semiconductor conduction. Electronic elements behave non-linearly, while the behavior of other electrical (non-electronic) elements is called linear. Electronics also deals with the function of electronic components themselves. Electronic components and circuits on a smaller scale are named with SI decimal prefixes according to the structure sizes , e.g. B. microelectronics (typically <100 micrometers ) or nanoelectronics (typically <100 nanometers ), which are usually connected to the integrated circuit z. B. silicon chip is realized.
Electronic circuits are usually built on circuit boards with the help of printed circuit boards and either assembled as a module to form electronic devices, or they become part of electrical equipment.
The term electronics is derived from the Greek word electron (ήλεκτρον), which means amber . Electronics is a suitcase word that was put together from the terms electron (the elementary particle) and technology . Electronics is, so to speak, electron technology.
In 1873, Willoughby Smith discovered that selenium was able to conduct light ( photoelectric effect ). Based on this knowledge, Karl Ferdinand Braun discovered the rectifier effect in 1874 . Stoney and Helmholtz coined the term electron as a carrier of electrical current . In 1883 Thomas Alva Edison received a patent for a DC voltage regulator based on glow emission (the Edison-Richardson effect ), a requirement for all vacuum tubes . In 1897 Karl Ferdinand Braun began developing the Braun tube . In 1899 the development of the tip diode began . In 1904, John Ambrose Fleming obtained a patent for a vacuum diode.
At the beginning of the 20th century, the development of electron tubes had already advanced. The first electron tubes were developed and already used in electrical circuits. With the triode , a useful component was available for the construction of amplifiers for the first time . This made inventions such as radio , television and radar possible.
The first transistor was presented in 1948 . Like tubes, transistors can be used as amplifiers, electronic switches or as oscillators . However, in contrast to vacuum tubes, which require a lot of space and electrical power, transistors can be manufactured very small, because they are based on semiconductor technology , which enables much higher current densities.
In the 1960s, complete circuits consisting of several transistors and other components were successfully manufactured on a single silicon crystal . The thus introduced technique of integrated circuits (IC short of Engl. Integrated Circuit ) has a steady since miniaturization performed. Today semiconductor electronics is the most important branch of electronics.
The important components include resistor , capacitor , transistor , diode , coil and the integrated circuit (IC for short). All of these components are offered in a wide variety of types. One component variant are the SMD components which, due to their mostly very compact design, are soldered directly to the surface of the circuit board.
We speak of passive components when primarily resistors, capacitors and inductors are meant. Among the active components usually all types of integrated circuits, semiconductor devices and electronic tubes are understood.
An independently and logically working computing operator chip is the modern processor , which is not only to be found on the mainboard of a computer, but is a component of modern industrial and vehicle technology .
Design of printed circuit boards and integrated circuits
Design automation of electronic systems is the German term for computer-assisted tools for the design of electronic systems, especially microelectronics . EDA is mostly understood as a branch of computer-aided design (CAD) or computer-aided engineering (CAE). Alternatively, ECAD ( electronic CAD ) is used instead of EDA .
The analog technology is mainly concerned with the processing of continuous signals. The physical laws that describe the behavior of the components (resistors, capacitors, transistors, tubes, etc.) are used, or favorable conditions are created through circuit principles. Typical basic circuits are current sources , current mirrors , differential amplifiers and cascades , as well as reference elements such as the band gap . More complicated circuits can be built from this, such as B. Amplifiers , which can be used to set up additional functions (oscillator, filter, etc.). The operational amplifier is an amplifier with a differential input (differential amplifier). Its name comes from the fact that mathematical operations (subtraction, addition, integration, etc.) can be carried out with it. Operational amplifiers are widely used in analog electronics. The accuracy of the signal processing in the analog electronics by the manufacturing tolerances of the components and their non-idealities (z. B. noise , nonlinearity , hysteresis ) as well as other disturbing effects such as crosstalk and couplings set of noise limits. Very advanced methods have been developed that compensate or minimize such errors and thus allow accuracies in precision electronics in the range of a few ppm . Such high accuracy is e.g. B. necessary to implement analog-digital converters with 20 bit resolution. In principle, analog technology forms the basis of digital technology.
Digital electronics, or digital technology, is concerned with processing discrete signals (expressed as numbers or logical values). The discretization always affects the range of values and often also the behavior over time. In practice one limits oneself to two-valued systems, i. This means that voltages or currents should - apart from transitional processes - only have two values (on / off, 1 or 0, also high / low, or H / L for short). In discrete-time systems, the values can only be changed at specific, mostly equidistant points in time, which are specified by a cycle. In digital electronics, analog signals are either digitized ( converted into digital signals ) prior to processing with the aid of analog-digital converters, or they already exist as discrete values from the outset. In digital technology, transistors are usually used as switching amplifiers and not as analog amplifiers.
The advantage of digital electronics lies in the fact that, following digitization, the disruptive effects mentioned in analog electronics no longer play a role, but at the expense of the component costs. Is z. If, for example, an analog circuit has a maximum error of 0.1%, this error can be undercut by digital circuits from a data width of approx. 10 bits . An analog multiplier requires about twenty transistors, a digital multiplier with the same accuracy more than twenty times that number. Digitalization initially increases the effort, but this is more than compensated for by the ever-increasing miniaturization. Today, a very large number of transistors can be implemented on an integrated circuit (the number is typically around 10 million). The advantage is that z. For example, the voltage levels can vary considerably without hindering the correct interpretation as 1 or 0. This makes it possible for the components of the integrated circuits to be very imprecise, which in turn enables further miniaturization. The properties of the circuit are thus largely decoupled from the physical properties of the components.
The simplified description of digital circuits with the two states H and L is not always sufficient to characterize or design them, especially at ever higher speeds and frequencies. In the borderline case, the circuit is in the transition between the two logically defined states for the greater part of the time. Therefore, in such cases, analog and high-frequency aspects have to be taken into account. Even with slow circuits there can be problems that can only be understood through analog approaches; An example is the problem of the metastability of flip-flops .
Logic of digital electronics
Digital circuits - also called switching systems or logic circuits - mainly consist of simple logic elements such as AND , NAND , NOR , OR or NOT gates and components with which digital signals can be stored, e.g. B. flip-flops or counters . All these logical functions can be implemented with electronic components (e.g. transistors) operating in so-called switch mode. By integrating these circuits on a chip (monolithic circuit), complex electronic components such as microprocessors are created .
High frequency electronics
High-frequency electronics or high-frequency technology is primarily concerned with the generation and transmission as well as the reception and processing of electromagnetic waves. Applications thereof are e.g. B. radio technology with radio , television , radar , remote control , wireless telephony, navigation, but also the avoidance of undesired vibrations (interference, EMC ) and uncontrolled radiation ( shielding ). Other areas of high-frequency electronics are microwave technology , cable-based information transmission or areas of medical electronics . The transition from low frequency to high frequency technology is fluid. It begins approximately when the frequency f of the electromagnetic wave on a connecting line of length L forms a product fL, which leads to a noticeable phase shift ßL = 2π L / λ and thus to standing waves. Here, λ = λ 0 / (ε r eff ) 1/2 is the wavelength on the line, λ 0 = c / f is the wavelength in free space and c is the speed of light in a vacuum. In the simplest case, depending on the field distribution, the variable ε r eff is calculated from a weighting of the various permittivity values ε r in the line. Even lines without loss can therefore only be neglected for a small phase shift ßL ≪ 1 (corresponds to approx. 57.3 °), i.e. only for fL ≪ c / [2π (ε r eff ) 1/2 ]. In the case of an electronic circuit with cables of L ≥ 3 m and ε r eff = ε r = 2.3, then for ßL <5 °, about f <1 MHz must then. stay. Practical high-frequency electronics therefore begins at around f = 1 MHz, and is a key pillar of information technology.
Even in the simplest case, two pieces of information are required to describe a line:
- Phase delay τ ph = (ε r eff ) 1/2 L / c
- Characteristic impedance Z 0
Z 0 and ε r eff can be calculated in a quasi-static model on circuit boards down to the lower GHz range from the line capacitance and line inductance per unit length. From a few gigahertz, the approximation is refined by using the Maxwell equations, the fields and the so-called eigenvalue ß with ß = (ε r eff ) 1/2 2π / λ 0 improved, frequency-dependent values ε r eff (f) and Z 0 (f) can be determined. From a few 10 GHz onwards, Maxwell's equations have to be solved numerically, the waves propagate in a zigzag, and multimode operation occurs completely analogously to fiber optics , for example when standing waves can also develop in the transverse direction. This applies to every line, more precisely, to every structure up to line branches, connection surfaces for components and for the structure of the components.
The components R, L and C lose their ideal properties U = RI, U = L dI / dt and I = C dU / dt between current I and voltage U, even in the SMD design from approx. 0.1 GHz. A resistor z. B. is always characterized by capacitive effects with increasing frequency and by inductive effects when the current flows. Electronic components are therefore measured beforehand in a substitute environment with 50 Ω connection cables (NWA = network analyzer), whereby the structure of the element must later be precisely reproduced in the actual circuit. The waves traveling on the connection lines, reflected on the object to be measured and transmitted through the object are linearly related with passive elements and non-linear elements (e.g. transistors) with only a small modulation: In a 2-port measurement, an NWA delivers then for each frequency a 2 × 2 scatter matrix (s-parameter), which in the case of non-linear elements still depends on the operating point and realistically describes the current-voltage behavior even for f> 50 GHz. This data is then mirrored into a CAD system that uses Kirchhoff's laws to determine all U and I. The elements L or C can be simulated for high frequencies by a line with ßL ≪ 1 and a short circuit or open circuit at the end and a resistance R can be implemented by a lossy line into which a wave runs and seeps into a swamp.
However, certain components and structures can also be taken over as finished models from a CAD system, provided that the models are trusted, which amounts to a considerable question of conscience, because the entire analysis depends on the models. In addition to ready-made models and NWA measurements, the fully numerical solution of Maxwell's equations can be used to carry out a “software measurement” of the s-parameters, so to speak, in passive structures. In order to keep the dramatically increasing computing time within limits, only the most critical areas are picked out in a structure: connection surfaces, crosses, plugs, antennas, branches, etc.
In the case of large-signal modulation of non-linear elements, the modeling according to SPICE, known from general electronics, can be tried up to a few gigahertz. The SPICE parameters that make the physical equations of the models "flexible" are to be selected so that the s-parameters of the SPICE model and NWA measurement match as closely as possible at all operating points and all frequencies: With only 10 Test working points and 50 frequency points each with 4 s parameters would result in 2000 complex s parameter values to be tested. The effort is enormous and the modeling extremely difficult, even for a single operating point.
The noise of electronic circuits can no longer be well described by SPICE models even at medium frequencies. Therefore, analogous to the NWA measurement, the noise behavior is measured in an equivalent environment (noise measuring station). With the noise parameters obtained (min. Noise figure with optimal generator impedance plus an equivalent noise resistance) it can be converted in the CAD system how the component in the actual circuit noise. A noise tester is very complex and requires an NWA a priori.
Evaluation of the many equations is impossible without the CAD systems. Sensible use also requires in-depth knowledge of the programmed theories and models used.
Power electronics refers to the branch of electrical engineering that has the task of converting electrical energy with electronic components. The conversion of electrical energy with transformers or with rotating machine sets, on the other hand, is not included in power electronics.
Microelectronics & Nanoelectronics
The Microelectronics is engaged in the development and manufacture of integrated circuits, typically with feature sizes or line widths of less than 100 microns . In some areas the 100- nanometer limit was not reached, so one speaks here formally of nanoelectronics . A silicon-based pic-electronics (<100 picometers ) will never be implemented, because z. B. with a structure width of 5 nm only about 20-25 silicon atoms (in ] of the diamond structure ) are connected to one another.
Importance in society
Electronics today covers countless areas, from semiconductor electronics to quantum electronics and nanoelectronics . Since the triumphant advance of the computer, the constant development of information technology and increasing automation, the importance of electronics has steadily expanded. Today electronics is very important in our society and it is impossible to imagine many areas without it.
Commercial electronics manufacturing
In 2007, 38% of all electronics manufactured in the world came from the Asia-Pacific region. In 1995 this proportion was still 20%. China alone increased its share from 3% in 1995 to 16% in 2007. South Korea, Malaysia, Singapore and Thailand are also among the top 10 countries. The share of Western Europe was 19% of global production in 2007 (corresponds to approx. 192 billion euros). The following ranking list (as of 2006) applies to the order of performance of the size of electronics manufacturing in Western Europe: Germany, France, Great Britain, Ireland, Italy.
Electronics and electrical engineering in the professional world
→ Main article: List of apprenticeships in electrical engineering
Further training to become an electrician takes place at a master ’s school and lasts 1 year full-time or 2 years part-time.
Further training to become an electrical engineer can be completed at a technical school in 4 full-time semesters or 8 semesters part-time.
Electronics is offered as a course of study at many universities , technical colleges and vocational academies . At universities, scientific work is emphasized during the course, at universities of applied sciences and vocational academies the focus is on the application of physical knowledge.
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