Electronics refers to the flow of charge (moving
electrons) through nonmetalconductors (mainly semiconductors), whereas electrical refers to the flow of charge through metalconductors. For example, flow of charge through silicon, which is not a metal, would come under electronics; whereas flow of charge through copper, which is a metal, would come under electrical. This distinction started around 1908with the invention by Lee De Forestof the triode. Until 1950this field was called "Radio technics" because its principal application was the design and theory of radio transmitters and receivers.
The study of new
semiconductordevices and related technology is considered a branch of physicswhereas the design and construction of electronic circuits to solve practical problems comes under electronics engineering. This article focuses on engineeringaspects of electronics.
Electronic devices and components
An electronic component is any physical entity in an electronic system whose intention is to affect the electrons or their associated fields in a desired manner consistent with the intended function of the electronic system. Components are generally intended to be in mutual electromechanical contact, usually by being soldered to a
printed circuit board(PCB), to create an electronic circuit with a particular function (for example an amplifier, radio receiver, or oscillator). Components may be packaged singly or in more complex groups as integrated circuits. Some common electronic components are capacitors, resistors, diodes, transistors etc.
Types of circuits
Most analog electronic appliances, such as
radioreceivers, are constructed from combinations of a few types of basic circuits. Analog circuits use a continuous range of voltage as opposed to discrete levels as in digital circuits.
The number of different analog circuits so far devised is huge, especially because a 'circuit' can be defined as anything from a single component, to systems containing thousands of components.
Analog circuits are sometimes called
linear circuits although many non-linear effects are used in analog circuits such as mixers, modulators, etc. Good examples of analog circuits include vacuum tube and transistor amplifiers, operational amplifiers and oscillators.
Some analog circuitry these days may use digital or even microprocessor techniques to improve upon the basic performance of the circuit. This type of circuit is usually called "mixed signal." Sometimes it may be difficult to differentiate between analog and digital circuits as they have elements of both linear and non-linear operation. An example is the comparator which takes in a continuous range of voltage but puts out only one of two levels as in a digital circuit. Similarly, an overdriven transistor amplifier can take on the characteristics of a controlled
switchhaving essentially two levels of output.
Digital circuits are electric circuits based on a number of discrete voltage levels. Digital circuits are the most common physical representation of Boolean algebra and are the basis of all digital computers. To most engineers, the terms "digital circuit", "digital system" and "logic" are interchangeable in the context of digital circuits.In most cases the number of different states of a node is two, represented by two voltage levels labeled "Low"(0) and "High"(1). Often "Low" will be near zero volts and "High" will be at a higher level depending on the supply voltage in use.
Computers, electronic clocks, and programmable logic controllers (used to control industrial processes) are constructed of digitalcircuits. Digital Signal Processors are another example.
Highly integrated devices:
Application-specific integrated circuit(ASIC)
Digital signal processor(DSP)
Field-programmable gate array(FPGA)
Heat dissipation and thermal management
Heatgenerated by electronic circuitry must be dissipated to prevent immediate failure and improve long term reliability. Techniques for heat dissipation can include heatsinks and fans for air cooling, and other forms of computer coolingsuch as water cooling. These techniques use convection, conduction, & radiationof heat energy.
Noise is associated with all electronic circuits. Noise is defined [IEEE Dictionary of Electrical and Electronics Terms ISBN-13: 978-0471428060] as unwanted disturbances superposed on a useful signal that tend to obscure its information content. Noise is not the same as signal distortion caused by a circuit.
Mathematical methods are integral to the study of electronics. To become proficient in electronics it is also necessary to become proficient in the mathematics of circuit analysis.
Circuit analysis is the study of methods of solving generally linear systems for unknown variables such as the voltage at a certain node or the current though a certain branch of a network. A common analytical tool for this is the
Also important to electronics is the study and understanding of
Computer aided design (CAD)
Today's electronics engineers have the ability to design circuits using premanufactured building blocks such as power supplies,
semiconductors (such as transistors), and integrated circuits. Electronic design automationsoftware programs include schematic captureprograms and printed circuit boarddesign programs. Popular names in the EDA software world are NI Multisim, Cadence ( ORCAD), Ea"gle PCB and Schematic, Mentor (PADS PCB and LOGIC Schematic), Altium (Protel), LabCentre Electronics (Proteus) and many others."
Many different methods of connecting components have been used over the years. For instance, early electronics often used point to point wiring with components attached to wooden breadboards to construct circuits. Cordwood construction and
wire wraps were other methods used. Most modern day electronics now use printed circuit boards (made of FR4), and highly integrated circuits. Health and environmental concerns associated with electronics assembly have gained increased attention in recent years, especially for products destined to the European Union, with its Restriction of Hazardous Substances Directive(RoHS) and Waste Electrical and Electronic Equipment Directive(WEEE), which went into force in July 2006.
Semiconductor sales leaders by year
Analog signal processing
Digital signal processing
Electronic Waste Recycling Fee
* IEEE - the Institute of Electrical and Electronics Engineers
List of 4000 series integrated circuits
List of 7400 series integrated circuits
2. The Art of Electronics ISBN-13: 978-0521370950
3. All New Electronics Self Teaching Guide ISBN-13: 978-0470289617
* [http://www.capacitorx.com/capacitors/ Capacitor Types and Tutorial]
* [http://www.audiocircuits.wikidot.com Audio Circuits] - [http://www.circuits.wikidot.com Circuits1] - [http://www.freecircuits.wikidot.com
* [http://www.electroniq.net Electronics tutorials, projects and software] Circuits2]
* [http://www.phy.davidson.edu/instrumentation/NEETS.htm Navy 1998 Navy Electricity and Electronics Training Series (NEETS)]
* DOE 1998 Electrical Science, Fundamentals Handbook, 4 vols.
** [http://hss.energy.gov/NuclearSafety/techstds/standard/hdbk1011/h1011v1.pdf Vol. 1, Basic Electrical Theory, Basic DC Theory]
** [http://hss.energy.gov/NuclearSafety/techstds/standard/hdbk1011/h1011v2.pdf Vol. 2, DC Circuits, Batteries, Generators, Motors]
** [http://hss.energy.gov/NuclearSafety/techstds/standard/hdbk1011/h1011v3.pdf Vol. 3, Basic AC Theory, Basic AC Reactive Components, Basic AC Power, Basic AC Generators]
** [http://hss.energy.gov/NuclearSafety/techstds/standard/hdbk1011/h1011v4.pdf Vol. 4, AC Motors, Transformers, Test Instruments & Measuring Devices, Electrical Distribution Systems]
* [http://www.ibiblio.org/obp/electricCircuits/ Lessons in Electric Circuits] - A free series of textbooks on the subjects of electricity and electronics.
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