Electronics and Electronic Engineering

Summary

A workable understanding of the phenomenon of electricity originated with proof that atoms were composed of smaller particles bearing positive and negative electrical charges. The modern field of electronics is essentially the science and technology of devices designed to control the movement of electricity to achieve some useful purpose. Initially, electronic technology consisted of devices that worked with continuously flowing electricity, whether direct or alternating current. Since the development of the transistor in 1947 and the integrated circuit in 1970, electronic technology has become digital, concurrent with the ability to assemble millions of transistor structures on the surface of a single silicon chip.

Definition and Basic Principles

The term “electronics” has acquired different meanings in different contexts. Fundamentally, “electronics” refers to the behavior of matter as affected by the properties and movement of electrons. More generally, electronics has come to mean the technology that has been developed to function according to electronic principles, especially pertaining to basic digital devices and the systems that they operate. The term “electronic engineering” refers to the practice of designing and building circuitry and devices that function on electronic principles.

The underlying principle of electronics derives from the basic structure of matter: that matter is composed of atoms composed in turn of smaller particles. The mass of atoms exists in the atomic nucleus, which is a structure composed of electrically neutral particles called neutrons and positively charged particles called protons. Isolated from the nuclear structure by a relatively immense distance is an equal number of negatively charged particles called electrons. Electrons are easily removed from atoms, and when a difference in electrical potential (voltage) exists between two points, electrons can move from the area of higher potential toward that of lower potential. This defines an electrical current.

Devices that control the presence and magnitude of voltages and currents are used to change the intrinsic form of the electrical signals generated. These devices also produce physical changes in materials that make the information carried by the electronic signal comprehensible.

Background and History

Archaeologists have found well-preserved Parthian relics that are believed to have been rudimentary but functional batteries. It is believed that the Parthians used these ancient devices to plate objects with gold. The knowledge was lost until 1800 when Italian physicist Alessandro Volta reinvented the voltaic pile. Danish physicist and chemist Hans Christian Ørsted demonstrated the relationship between electricity and magnetism in 1820. In 1821, British physicist and chemist Michael Faraday used that relationship to explain the electromagnetic principle on which all electric motors work. In 1831, he demonstrated the reverse relationship, inventing the electrical generator in the process.

Electricity was thought by American statesman and scientist Benjamin Franklin and many other scientists of the eighteenth and nineteenth centuries to be some mysterious kind of fluid that might be captured and stored. A workable concept of electricity was not developed until 1897 when English physicist J. J. Thomson identified cathode rays as streams of light electrical particles that must have come from within the atoms of their source materials. He arbitrarily ascribed their electrical charge as negative. Thomson also identified channel rays as streams of massive particles from within the atoms of their source materials endowed with the opposite electrical charge of the electrons that made up cathode rays. These observations essentially proved that atoms have substructures. They also provided a means of explaining electricity as the movement of charged particles from one location to another.

With the establishment of an electrical grid, based on the advocacy of alternating current by Serbian American engineer and inventor Nikola Tesla (1856–1943), a vast assortment of analog electrical devices were soon developed for consumer use, though initially, these devices were no more than electric lights and electromechanical applications based on electric motors and generators.

As the quantum theory of atomic structure came to be better understood and electricity better controlled, electronic theory became much more important. Spurred by the success of the electromagnetic telegraph of American inventor Samuel Morse (1791–1872), scientists sought other applications. The first major electronic application of worldwide importance was wireless radio, first demonstrated by Italian inventor Guglielmo Marconi (1874–1937). Radio depended on electronic devices known as vacuum tubes, in which structures capable of controlling currents and voltages could operate at high temperatures in an evacuated tube with external contacts. In 1947, American physicist William Shockley and colleagues invented the semiconductor-based transistor, which could be made to function in the same manner as vacuum tube devices, but without the high temperatures, electrical power consumption, and vacuum construction of those analog devices.

In 1970, the first integrated circuit “chips” were made by constructing very small transistor structures on the surface of a silicon chip. This gave rise to the entire digital technology that powers the modern world.

Applications and Products

Electronics are applied in practically every conceivable manner today, based on their utility in converting easily produced electrical current into mechanical movement, sound, light, and information signals.

Basic Electronic Devices. Transistor-based digital technology has replaced older vacuum tube technology, except in rare instances in which a transistorized device cannot perform the same function. Electronic circuits based on vacuum tubes could carry out essentially the same individual operations as transistors, but they were severely limited by physical size, heat production, energy consumption, and mechanical failure. Nevertheless, vacuum tube technology was the basic technology that produced radio, television, radar, X-ray machines, and a broad variety of other electronic applications.

Electronic devices that did not use vacuum tube technology but operated on electronic and electromagnetic principles were, and still are, numerous. These devices include electromagnets and all electric motors and generators. The control systems for many such devices generally consisted of switching circuits and indicator lights. More advanced and highly sensitive devices required control systems that utilized more refined and correspondingly sensitive capabilities available with vacuum tube technology.

Circuit Boards. The basic principles of electricity, such as Ohm's resistance law and Kirchoff's current law and capacitance and inductance, are key features in the functional design and engineering of analog electronic systems, especially for vacuum-tube control systems. An important application that facilitated the general use and development of electronic systems of all kinds is printed circuit board technology. A printed circuit board accepts standardized components onto a nonconducting platform made initially of compressed fiberboard, which was eventually replaced by a resin-based composite board. A circuit design is photo-etched onto a copper sheet that makes up one face of the circuit board, and all nonetched copper is chemically removed from the surface of the board, leaving the circuit pattern. The leads of circuit components such as resistors, capacitors, and inductors are inserted into the circuit pattern and secured with solder connections.

Mass production requirements developed the flotation soldering process, whereby preassembled circuit boards are floated on a bed of molten solder, which automatically completes all solder connections at once with a high degree of consistency. This has become the most important means of circuit board production since the development of transistor technology, being highly compatible with mechanization and automation and with the physical shapes and dimensions of integrated circuit (IC) chips and other components.

Digital Devices. Semiconductor-based transistors comprise the heart of modern electronics and electronic engineering. Unlike vacuum tubes, transistors do not work on a continuous electrical signal. Instead, they function exceedingly well as simple on-off switches that are easily controlled. This makes them well-adapted to functions based on Boolean algebra. All transistor structures consist of a series of “gates” that perform a specific function on the electronic signals that are delivered to them.

Digital devices represent the most common (and rapidly growing) application of electronics and electronic engineering, including relatively simple consumer electronic devices such as compact fluorescent light bulbs and motion-detecting air fresheners to the most advanced computers and analytical instrumentation. All applications, however, utilize an extensive, but limited, assortment of digital components in the form of IC chips that have been designed to carry out specific actions with electrical or electromagnetic input signals.

Input signals are defined by the presence or absence of a voltage or a current, depending upon the nature of the device. Inverter gates reverse the sense of the input signal, converting an input voltage (high input) into an output signal of no voltage (low output) and vice versa. Other transistor structures (gates) called AND, NAND, OR, NOR, and X-OR function to combine input signals in different ways to produce corresponding output signals. More advanced devices (for example, counters and shift registers) use combinations of the different gates to construct various functional circuits that accumulate or manipulate signal information in various ways.

One of the most useful digital IC components is the operational amplifier or op-amp. Op-amps contain transistor-based circuitry that boosts the magnitude of an input signal, either voltage or current, by five orders of magnitude (100,000 times) or more. They are the basis of the exceptional sensitivity of modern analytical instruments used in all fields of science and technology.

Electrical engineers are involved in all aspects of the design and development of electronic equipment. Engineers act first as the inventors and designers of electronic systems, conceptualizing the specific functions a potential system will be required to carry out. This process moves through the specification of the components required for the system's functionality to the design of new system devices. The design parameters extend to the infrastructure that must support the system in operation. Engineers determine the standards of safety, integrity, and operation that must be met for electronic systems.

Consumer Electronics. For the most part, the term “electronics” is commonly used to refer to the electronic devices developed for retail sale to consumers. These devices include televisions, audio systems, mobile phones, cameras and camcorders, laptops, tablets, computers, printers, scanners, fax and copy machines, and cash registers. Millions of such devices are sold around the world each day, and numerous other businesses have formed to support their operation.

Aerospace Industry. Electronic devices are used in spacecraft, satellites, and aircraft power management systems.

Medical care. Advancements in electronics in the medical field have eased the medical examination of patients. Several instruments and devices like nuclear magnetic resonance (NMR), X-rays, pacemakers, and magnetic resonance imaging (MRI) are based on electronics. Additionally, surgical robots are increasing in popularity.

Automobiles. Electronics are used throughout automobiles, including in the engine, transmission, and safety systems. As climate concerns lead to further governmental climate policies, demand will increase for sustainable automotive options.

Agriculture. Applications of electronics in agriculture include crop monitoring and the measurement of salinity, moisture, and nutrition level of soils to enhance agricultural productivity.

Communication. Electronic devices are used in radio, television systems, and telecommunications for long-distance communications.

Military. Electronic devices like drones and uncrewed aerial vehicles (UAVs) are used in the military for aerial reconnaissance, attacks, and monitoring. With growing cyber security concerns, electrical engineers with cyber-physical security expertise are in demand to protect military infrastructure.

Social Context and Future Prospects

It is difficult, if not impossible, to imagine modern society without electronic technology. Electronics enable instant communication, wherein a person can communicate directly and almost instantaneously with someone on the other side of the world. As a social tool, such facile communication has the potential to bring about understanding between people in a way that was once science fiction. Social networking sites, for example, bring people from widely varied backgrounds together in a common forum. However, network hackers and cybercriminals can also use electronic technology to steal personal data and disrupt financial markets.

Electronics themselves are not the problem, for it is only a tool. Though built on a foundation unlikely to change significantly, electronic technology will be transformed into newer and better applications. Newer electronic principles will come to the fore. For example, materials such as graphene and quantum dots are expected to provide entirely newer means of constructing transistor structures at the atomic and molecular levels. Compared with the 50- to 100-nanometer size of transistor technology, these newer levels would represent a difference of several orders of magnitude. Moreover, research has indicated the potential use of compound semiconductors, including indium phosphide or gallium nitride, with a thickness of 10 nanometers in heterojunction bipolar transistors. These are expected to function at the speed of more than 300 gigahertz, thereby facilitating optical fiber communication and fifth-generation (5G) telecommunication technologies. Researchers suggest that this sort of refinement in scale could produce magnetic memory devices that can store as much as ten terabits of information in one square centimeter of disk surface.

Electrical engineers are increasingly in demand across industries as organizations seek sustainable, innovative solutions. Wide bandgap (WBG) semiconductors are increasingly in demand in renewable energy, smart grids, and industrial automation. Additionally, modern electrical engineering intersects the fields of artificial intelligence and biology. For example, electronic equipment sensor data can be analyzed using artificial intelligence. Electrical engineers increasingly help develop biocompatible medical devices like pacemakers.

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