From Wikipedia, the free encyclopedia Electronics
Electronics
problems come under electronics engineering. This arti-
cle focuses on engineering aspects of electronics.
Electronic devices and compo-
nents
An electronic component is any physical entity in an
electronic system used to affect the electrons or their as-
sociated fields in a desired manner consistent with the
intended function of the electronic system. Components
are generally intended to be connected together, usually
by being soldered to a printed circuit board (PCB), to
create an electronic circuit with a particular function
Surface mount electronic components (for example an amplifier, radio receiver, or oscillator).
Components may be packaged singly or in more complex
Electronics is the branch of science, engineering and groups as integrated circuits. Some common electronic
technology that deals with electrical circuits involving components are capacitors, inductors, resistors, diodes,
active electrical components such as vacuum tubes, tran- transistors, etc. Components are often categorized as ac-
sistors, diodes and integrated circuits, and associated tive (e.g. transistors and thyristors) or passive (e.g. resis-
passive interconnection technologies. The nonlinear be- tors and capacitors).
haviour of active components and their ability to control
electron flows makes amplification of weak signals possi- Early electronic components
ble and is usually applied to information and signal pro-
cessing. Similarly, the ability of electronic devices to act Vacuum tubes were one of the earliest electronic compo-
as switches makes digital information processing possi- nents. They dominated electronics until the 1950s. Since
ble. Interconnection technologies such as circuit boards, that time, solid state devices have all but completely tak-
electronics packaging technology, and other varied en over. Vacuum tubes are still used in some specialist
forms of communication infrastructure complete circuit applications such as high power RF amplifiers, cathode
functionality and transform the mixed components into ray tubes, and some microwave devices.
a working system.
Electronics is distinct from electrical and electro-me- Types of circuits
chanical science and technology, which deals with the
generation, distribution, switching, storage and conver- Circuits and components can be divided into two groups:
sion of electrical energy to and from other energy forms analog and digital. A particular device may consist of cir-
using wires, motors, generators, batteries, switches, re- cuitry that has one or the other or a mix of the two types.
lays, transformers, resistors and other passive compo-
nents. This distinction started around 1906 with the in- Analog circuits
vention by Lee De Forest of the triode, which made elec- Main article: Analog electronics
trical amplification of weak radio signals and audio sig- Most analog electronic appliances, such as radio re-
nals possible with a non-mechanical device. Until 1950 ceivers, are constructed from combinations of a few
this field was called "radio technology" because its prin- types of basic circuits. Analog circuits use a continuous
cipal application was the design and theory of radio range of voltage as opposed to discrete levels as in digital
transmitters, receivers and vacuum tubes. circuits.
Today, most electronic devices use semiconductor The number of different analog circuits so far devised
components to perform electron control. The study of is huge, especially because a ’circuit’ can be defined as
semiconductor devices and related technology is consid- anything from a single component, to systems contain-
ered a branch of solid state physics, whereas the design ing thousands of components.
and construction of electronic circuits to solve practical Analog circuits are sometimes called linear circuits
although many non-linear effects are used in analog cir-
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From Wikipedia, the free encyclopedia Electronics
clocks, and programmable logic controllers (used to con-
trol industrial processes) are constructed of digital cir-
cuits. Digital signal processors are another example.
Building blocks:
• Logic gates
• Adders
• Flip-Flops
• Counters
• Registers
• Multiplexers
• Schmitt triggers
Highly integrated devices:
• Microprocessors
• Microcontrollers
• Application-specific integrated circuit (ASIC)
• Digital signal processor (DSP)
• Field-programmable gate array (FPGA)
Heat dissipation and thermal
management
Hitachi J100 adjustable frequency drive chassis. Main article: Thermal management of electronic devices
and systems
cuits such as mixers, modulators, etc. Good examples of Heat generated by electronic circuitry must be dissipated
analog circuits include vacuum tube and transistor am- to prevent immediate failure and improve long term re-
plifiers, operational amplifiers and oscillators. liability. Techniques for heat dissipation can include heat
One rarely finds modern circuits that are entirely sinks and fans for air cooling, and other forms of comput-
analog. These days analog circuitry may use digital or er cooling such as water cooling. These techniques use
even microprocessor techniques to improve perfor- convection, conduction, & radiation of heat energy.
mance. This type of circuit is usually called "mixed sig-
nal" rather than analog or digital.
Sometimes it may be difficult to differentiate be-
Noise
tween analog and digital circuits as they have elements Main article: Electronic noise
of both linear and non-linear operation. An example is Noise is associated with all electronic circuits. Noise is
the comparator which takes in a continuous range of defined[1] as unwanted disturbances superposed on a
voltage but only outputs one of two levels as in a digital useful signal that tend to obscure its information con-
circuit. Similarly, an overdriven transistor amplifier can tent. Noise is not the same as signal distortion caused by
take on the characteristics of a controlled switch having a circuit. Noise may be electromagnetically or thermally
essentially two levels of output. generated, which can be decreased by lowering the op-
erating temperature of the circuit. Other types of noise,
Digital circuits such as shot noise cannot be removed as they are due to
Main article: Digital electronics limitations in physical properties.
Digital circuits are electric circuits based on a number of
discrete voltage levels. Digital circuits are the most com- Electronics theory
mon physical representation of Boolean algebra and are
the basis of all digital computers. To most engineers, the Main article: Mathematical methods in electronics
terms "digital circuit", "digital system" and "logic" are Mathematical methods are integral to the study of elec-
interchangeable in the context of digital circuits. Most tronics. To become proficient in electronics it is also nec-
digital circuits use a binary system with two voltage lev- essary to become proficient in the mathematics of circuit
els labeled "0" and "1". Often logic "0" will be a lower analysis.
voltage and referred to as "Low" while logic "1" is re- Circuit analysis is the study of methods of solving
ferred to as "High". However, some systems use the re- generally linear systems for unknown variables such as
verse definition ("0" is "High") or are current based. the voltage at a certain node or the current through a
Ternary (with three states) logic has been studied, and certain branch of a network. A common analytical tool
some prototype computers made. Computers, electronic for this is the SPICE circuit simulator.
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From Wikipedia, the free encyclopedia Electronics
Also important to electronics is the study and under-
standing of electromagnetic field theory.
See also
• Atomtronics • Marine electronics
Electronics lab • Audio
engineering
•
•
Power electronics
Printed circuit board
Main article: Electronics lab simulation • Broadcast • Robotics
Due to the empirical nature of electronics theory, labo- engineering • Waste Electrical and Electronic
ratory experimentation is an important part of the study • Computer Equipment Directive
of electronics. These experiments are used to prove, ver- engineering
ify, and reinforce laws and theorems such as Ohm’s law, • Electronic
Kirchhoff’s laws, etc. Historically, electronics labs have engineering
consisted of electronics devices and equipment located • Index of
in a physical space, although in more recent years the electronics
trend has been towards electronics lab simulation soft- articles
ware, such as CircuitLogix, Multisim, and PSpice.
References
Computer aided design (CAD) [1] IEEE Dictionary of Electrical and Electronics Terms
Main article: Electronic design automation ISBN 978-0-471-42806-0
Today’s electronics engineers have the ability to design
circuits using premanufactured building blocks such as
power supplies, semiconductors (such as transistors), Further reading
and integrated circuits. Electronic design automation • The Art of Electronics ISBN 978-0-521-37095-0
software programs include schematic capture programs • Online course on Computational Electronics on
and printed circuit board design programs. Popular Nanohub.org
names in the EDA software world are NI Multisim,
Cadence (ORCAD), Eagle PCB and Schematic, Mentor
(PADS PCB and LOGIC Schematic), Altium (Protel),
External links
LabCentre Electronics (Proteus), gEDA, KiCad and many • Electrical and electronics web portal
others. • Electronics tutorials, projects and software
• Navy 1998 Navy Electricity and Electronics Training
Construction methods Series (NEETS)
• DOE 1998 Electrical Science, Fundamentals
Main article: Electronic packaging Handbook, 4 vols.
Many different methods of connecting components have • Vol. 1, Basic Electrical Theory, Basic DC Theory
been used over the years. For instance, early electronics • Vol. 2, DC Circuits, Batteries, Generators, Motors
often used point to point wiring with components at- • Vol. 3, Basic AC Theory, Basic AC Reactive
tached to wooden breadboards to construct circuits. Components, Basic AC Power, Basic AC
Cordwood construction and wire wraps were other Generators
methods used. Most modern day electronics now use • Vol. 4, AC Motors, Transformers, Test
printed circuit boards made of materials such as FR4, Instruments & Measuring Devices, Electrical
or the cheaper (and less hard-wearing) Synthetic Resin Distribution Systems
Bonded Paper (SRBP, also known as Paxoline/Paxolin • Electronics at the Open Directory Project
(trade marks) and FR2) - characterised by its light yellow-
to-brown colour. Health and environmental concerns as-
sociated with electronics assembly have gained increased
attention in recent years, especially for products des-
tined to the European Union, with its Restriction of
Hazardous Substances Directive (RoHS) and Waste Elec-
trical and Electronic Equipment Directive (WEEE), which
went into force in July 2006.
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Categories:
• Electronics
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From Wikipedia, the free encyclopedia Electronics
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