Tuesday, April 22, 2008
Electronic circuit
Electronic circuit
Electronic Circuit
An electronic circuit is an electrical circuit that connects active and passive electronic components such as resistors, capacitors, microprocessors, transistors or vacuum tubes.
The electronic circuits are typically built using a printed circuit board (PCB) that is used to mechanically support and electrically connect electronic components.
The continued miniaturization and savings in power allows electronic circuits to be packaged more densely, making possible compact computers, advanced radar and navigation systems, and other devices that use very large numbers of components (see microelectronics).
Electronic circuits can display highly complex behaviors, even though they are governed by the same laws as simple electrical circuits.
Electronic circuits can usually be categorized as analog, digital, or mixed-signal (a combination of analog and digital) electronic circuits.
Contents
1 Analog circuits
2 Digital circuits
3 Mixed-signal circuits
4 3 Basic Parts
5 External Links
Analog circuits
Analog electronic circuits are those in which electric signals vary continuously to correspond to the information being represented. Electronic equipment like voltage amplifiers, power amplifiers, tuning circuits, radios, and televisions are largely analog (with the exception of their control sections, which may be digital, especially in modern units).
The basic units of analog circuits are passive (resistors, capacitors, inductors) and active (independent power sources and dependent power sources). Components such as transistors may be represented by a model containing passive components and dependent sources. Another classification is to take impedance and independent sources and opamp as basic electronic components; this allows us to model frequency dependent negative resistors, gyrators, negative impedance converters, and dependent sources as secondary electronic components.
Digital circuits
In digital electronic circuits, electric signals take on discrete values to represent logical and numeric values that represent the information to be processed. Transistors are used primarily as switches to make logic gates. Examples of electronic equipment which use digital circuits include digital wristwatches, calculators and PDAs, and microprocessors.
Mixed-signal circuits
Mixed-signal or hybrid circuits contain elements of both analog and digital circuits. Examples include comparators, timers, PLLs, ADCs (analog-to-digital converters), and DACs (digital-to-analog converters).
3 Basic Parts
Energy source - converts nonelectric energy into energy. examples are batteries and generators.
Output device - uses electric energy to do work and a connection. examples are motor and lamp.
Connection - allows electric current to flow. examples are wire and cable.
External Links
CircuitsArchive - Public Archive of Electronic Circuits for the hobbyist.
This electronics-related article is a stub. You can help Wikipedia by expanding it.
This article about an engineering topic is a stub. You can help Wikipedia by expanding it.
Electrical engineering
Electrical engineering
Electrical Engineers design power systems...
... and complex electronic circuits.
Electrical engineering — sometimes referred to as electrical and electronic engineering — is an engineering field that deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical power supply. The field now covers a range of sub-studies including power, electronics, control systems, signal processing and telecommunications.
Electrical engineering may or may not encompass electronic engineering. Where a distinction is made, usually outside of the United States, electrical engineering is considered to deal with the problems associated with large-scale electrical systems such as power transmission and motor control, whereas electronic engineering deals with the study of small-scale electronic systems including computers and integrated circuits.[1] Another way of looking at the distinction is that electrical engineers are usually concerned with using electricity to transmit energy, while electronic engineers are concerned with using electricity to transmit information.
Contents
1 History
1.1 Modern developments
2 Education
3 Practicing engineers
4 Tools and work
5 Sub-disciplines
5.1 Power
5.2 Control
5.3 Electronics
5.4 Microelectronics
5.5 Signal processing
5.6 Telecommunications
5.7 Instrumentation engineering
5.8 Computers
6 Related disciplines
7 See also
8 References
9 External links
History
Main article: History of electrical engineering
Electricity has been a subject of scientific interest since at least the early 17th century. The first electrical engineer was probably William Gilbert who designed the versorium: a device that detected the presence of statically charged objects. He was also the first to draw a clear distinction between magnetism and static electricity and is credited with establishing the term electricity.[2] In 1775 Alessandro Volta's scientific experimentations devised the electrophorus, a device that produced a static electric charge, and by 1800 Volta developed the voltaic pile, a forerunner of the electric battery.[3]
However, it was not until the 19th century that research into the subject started to intensify. Notable developments in this century include the work of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor, Michael Faraday, the discoverer of electromagnetic induction in 1831, and James Clerk Maxwell, who in 1873 published a unified theory of electricity and magnetism in his treatise Electricity and Magnetism.[4]
During these years, the study of electricity was largely considered to be a subfield of physics. It was not until the late 19th century that universities started to offer degrees in electrical engineering. The Darmstadt University of Technology founded the first chair and the first faculty of electrical engineering worldwide in 1882. In 1883 Darmstadt University of Technology and Cornell University introduced the world's first courses of study in electrical engineering, and in 1885 the University College London founded the first chair of electrical engineering in the United Kingdom.[5] The University of Missouri subsequently established the first department of electrical engineering in the United States in 1886.[6]
Thomas Edison built the world's first large-scale electrical supply network
During this period, the work concerning electrical engineering increased dramatically. In 1882, Edison switched on the world's first large-scale electrical supply network that provided 110 volts direct current to fifty-nine customers in lower Manhattan. In 1887, Nikola Tesla filed a number of patents related to a competing form of power distribution known as alternating current. In the following years a bitter rivalry between Tesla and Edison, known as the "War of Currents", took place over the preferred method of distribution. AC eventually replaced DC for generation and power distribution, enormously extending the range and improving the safety and efficiency of power distribution.
Nikola Tesla made long-distance electrical transmission networks possible.
The efforts of the two did much to further electrical engineering—Tesla's work on induction motors and polyphase systems influenced the field for years to come, while Edison's work on telegraphy and his development of the stock ticker proved lucrative for his company, which ultimately became General Electric. However, by the end of the 19th century, other key figures in the progress of electrical engineering were beginning to emerge.[7]
Modern developments
Emergence of radio and electronics
During the development of radio, many scientists and inventors contributed to radio technology and electronics. In his classic UHF experiments of 1888, Heinrich Hertz transmitted (via a spark-gap transmitter) and detected radio waves using electrical equipment. In 1895, Nikola Tesla was able to detect signals from the transmissions of his New York lab at West Point (a distance of 80.4 km / 49.95 miles).[8] In 1897, Karl Ferdinand Braun introduced the cathode ray tube as part of an oscilloscope, a crucial enabling technology for electronic television.[9] John Fleming invented the first radio tube, the diode, in 1904. Two years later, Robert von Lieben and Lee De Forest independently developed the amplifier tube, called the triode.[10] In 1895, Guglielmo Marconi furthered the art of hertzian wireless methods.[11][12] In 1920 Albert Hull developed the magnetron which would eventually lead to the development of the microwave oven in 1946 by Percy Spencer.[13][14] In 1934 the British military began to make strides towards radar (which also uses the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station at Bawdsey in August 1936.[15]
In 1941 Konrad Zuse presented the Z3, the world's first fully functional and programmable computer.[16] In 1946 the ENIAC (Electronic Numerical Integrator and Computer) of John Presper Eckert and John Mauchly followed, beginning the computing era. The arithmetic performance of these machines allowed engineers to develop completely new technologies and achieve new objectives, including the Apollo missions and the NASA moon landing.[17]
The invention of the transistor in 1947 by William B. Shockley, John Bardeen and Walter Brattain opened the door for more compact devices and led to the development of the integrated circuit in 1958 by Jack Kilby and independently in 1959 by Robert Noyce.[18] In 1968 Marcian Hoff invented the first microprocessor at Intel and thus ignited the development of the personal computer. The first realization of the microprocessor was the Intel 4004, a 4-bit processor developed in 1971, but only in 1973 did the Intel 8080, an 8-bit processor, make the building of the first personal computer, the Altair 8800, possible.[19]
Education
Electrical engineers typically possess an academic degree with a major in electrical engineering. The length of study for such a degree is usually four or five years and the completed degree may be designated as a Bachelor of Engineering, Bachelor of Science, Bachelor of Technology or Bachelor of Applied Science depending upon the university. The degree generally includes units covering physics, mathematics, computer science, project management and specific topics in electrical engineering. Initially such topics cover most, if not all, of the sub-disciplines of electrical engineering. Students then choose to specialize in one or more sub-disciplines towards the end of the degree.
Some electrical engineers also choose to pursue a postgraduate degree such as a Master of Engineering/Master of Science (MEng/MSc), a Master of Engineering Management, a Doctor of Philosophy (PhD) in Engineering, an Engineering Doctorate (EngD), or an Engineer's degree. The Master and Engineer's degree may consist of either research, coursework or a mixture of the two. The Doctor of Philosophy and Engineering Doctorate degrees consist of a significant research component and are often viewed as the entry point to academia. In the United Kingdom and various other European countries, the Master of Engineering is often considered an undergraduate degree of slightly longer duration than the Bachelor of Engineering.[20]
Practicing engineers
In most countries, a Bachelor's degree in engineering represents the first step towards professional certification and the degree program itself is certified by a professional body. After completing a certified degree program the engineer must satisfy a range of requirements (including work experience requirements) before being certified. Once certified the engineer is designated the title of Professional Engineer (in the United States, Canada and South Africa ), Chartered Engineer (in India, the United Kingdom, Ireland and Zimbabwe), Chartered Professional Engineer (in Australia and New Zealand) or European Engineer (in much of the European Union).
The advantages of certification vary depending upon location. For example, in the United States and Canada "only a licensed engineer may seal engineering work for public and private clients".[21] This requirement is enforced by state and provincial legislation such as Quebec's Engineers Act.[22] In other countries, such as Australia, no such legislation exists. Practically all certifying bodies maintain a code of ethics that they expect all members to abide by or risk expulsion.[23] In this way these organizations play an important role in maintaining ethical standards for the profession. Even in jurisdictions where certification has little or no legal bearing on work, engineers are subject to contract law. In cases where an engineer's work fails he or she may be subject to the tort of negligence and, in extreme cases, the charge of criminal negligence. An engineer's work must also comply with numerous other rules and regulations such as building codes and legislation pertaining to environmental law.
Professional bodies of note for electrical engineers include the Institute of Electrical and Electronics Engineers (IEEE) and the Institution of Engineering and Technology (IET) (which was formed by the merging of the Institution of Electrical Engineers (IEE) and the Institution of Incorporated Engineers (IIE). The IEEE claims to produce 30% of the world's literature in electrical engineering, has over 360,000 members worldwide and holds over 3,000 conferences annually.[24] The IET publishes 21 journals, has a worldwide membership of over 150,000, and claims to be the largest professional engineering society in Europe.[25][26] Obsolescence of technical skills is a serious concern for electrical engineers. Membership and participation in technical societies, regular reviews of periodicals in the field and a habit of continued learning are therefore essential to maintaining proficiency.[27]
In countries such as Australia, Canada and the United States electrical engineers make up around 0.25% of the labor force (see note). Outside of these countries, it is difficult to gauge the demographics of the profession due to less meticulous reporting on labour statistics. However, in terms of electrical engineering graduates per-capita, electrical engineering graduates would probably be most numerous in countries such as Taiwan, Japan, India and South Korea.[28]
Tools and work
From the Global Positioning System to electric power generation, electrical engineers have contributed to the development of a wide range of technologies. They design, develop, test and supervise the deployment of electrical systems and electronic devices. For example, they may work on the design of telecommunication systems, the operation of electric power stations, the lighting and wiring of buildings, the design of household appliances or the electrical control of industrial machinery.[29]
Satellite communications is one of many projects an electrical engineer might work on
Fundamental to the discipline are the sciences of physics and mathematics as these help to obtain both a qualitative and quantitative description of how such systems will work. Today most engineering work involves the use of computers and it is commonplace to use computer-aided design programs when designing electrical systems. Nevertheless, the ability to sketch ideas is still invaluable for quickly communicating with others.
Although most electrical engineers will understand basic circuit theory (that is the interactions of elements such as resistors, capacitors, diodes, transistors and inductors in a circuit), the theories employed by engineers generally depend upon the work they do. For example, quantum mechanics and solid state physics might be relevant to an engineer working on VLSI (the design of integrated circuits), but are largely irrelevant to engineers working with macroscopic electrical systems. Even circuit theory may not be relevant to a person designing telecommunication systems that use off-the-shelf components. Perhaps the most important technical skills for electrical engineers are reflected in university programs, which emphasize strong numerical skills, computer literacy and the ability to understand the technical language and concepts that relate to electrical engineering.
For many engineers, technical work accounts for only a fraction of the work they do. A lot of time may also be spent on tasks such as discussing proposals with clients, preparing budgets and determining project schedules.[30] Many senior engineers manage a team of technicians or other engineers and for this reason project management skills are important. Most engineering projects involve some form of documentation and strong written communication skills are therefore very important.
The workplaces of electrical engineers are just as varied as the types of work they do. Electrical engineers may be found in the pristine lab environment of a fabrication plant, the offices of a consulting firm or on site at a mine. During their working life, electrical engineers may find themselves supervising a wide range of individuals including scientists, electricians, computer programmers and other engineers.
Sub-disciplines
Electrical engineering has many sub-disciplines, the most popular of which are listed below. Although there are electrical engineers who focus exclusively on one of these sub-disciplines, many deal with a combination of them. Sometimes certain fields, such as electronic engineering and computer engineering, are considered separate disciplines in their own right.
Power
Main article: Power engineering
Power engineering deals with the generation, transmission and distribution of electricity as well as the design of a range of related devices. These include transformers, electric generators, electric motors, high voltage engineering and power electronics. In many regions of the world, governments maintain an electrical network called a power grid that connects a variety of generators together with users of their energy. Users purchase electrical energy from the grid, avoiding the costly exercise of having to generate their own. Power engineers may work on the design and maintenance of the power grid as well as the power systems that connect to it. Such systems are called on-grid power systems and may supply the grid with additional power, draw power from the grid or do both. Power engineers may also work on systems that do not connect to the grid, called off-grid power systems, which in some cases are preferable to on-grid systems. The future includes Satellite controlled power systems, with feedback in real time to prevent power surges and prevent blackouts.
Control
Main article: Control engineering
Control engineering focuses on the modeling of a diverse range of dynamic systems and the design of controllers that will cause these systems to behave in the desired manner. To implement such controllers electrical engineers may use electrical circuits, digital signal processors, microcontrollers and PLCs (Programmable Logic Controllers). Control engineering has a wide range of applications from the flight and propulsion systems of commercial airliners to the cruise control present in many modern automobiles. It also plays an important role in industrial automation.
Control engineers often utilize feedback when designing control systems. For example, in an automobile with cruise control the vehicle's speed is continuously monitored and fed back to the system which adjusts the motor's power output accordingly. Where there is regular feedback, control theory can be used to determine how the system responds to such feedback.
Electronics
Main article: Electronic engineering
Electronic engineering involves the design and testing of electronic circuits that use the properties of components such as resistors, capacitors, inductors, diodes and transistors to achieve a particular functionality. The tuned circuit, which allows the user of a radio to filter out all but a single station, is just one example of such a circuit. Another example (of a pneumatic signal conditioner) is shown in the adjacent photograph.
Prior to the second world war, the subject was commonly known as radio engineering and basically was restricted to aspects of communications and radar, commercial radio and early television. Later, in post war years, as consumer devices began to be developed, the field grew to include modern television, audio systems, computers and microprocessors. In the mid to late 1950s, the term radio engineering gradually gave way to the name electronic engineering.
Before the invention of the integrated circuit in 1959, electronic circuits were constructed from discrete components that could be manipulated by humans. These discrete circuits consumed much space and power and were limited in speed, although they are still common in some applications. By contrast, integrated circuits packed a large number—often millions—of tiny electrical components, mainly transistors, into a small chip around the size of a coin. This allowed for the powerful computers and other electronic devices we see today.
Microelectronics
Main article: Microelectronics
Microelectronics engineering deals with the design of very small electronic circuit components for use in an integrated circuit or sometimes for use on their own as a general electronic component. The most common microelectronic components are semiconductor transistors, although all main electronic components (resistors, capacitors, inductors) can be created at a microscopic level.
Microelectronic components are created by chemically fabricating wafers of semiconductors such as silicon (at higher frequencies, compound semiconductors like gallium arsenide and indium phosphide) to obtain the desired transport of electronic charge and control of current. The field of microelectronics involves a significant amount of chemistry and material science and requires the electronic engineer working in the field to have a very good working knowledge of the effects of quantum mechanics.
Signal processing
A Bayer filter on a CCD requires signal processing to get a red, green, and blue value at each pixel
Main article: Signal processing
Signal processing deals with the analysis and manipulations of signals. Signals can be either analog, in which case the signal varies continuously according to the information, or digital, in which case the signal varies according to a series of discrete values representing the information. For analog signals, signal processing may involve the amplification and filtering of audio signals for audio equipment or the modulation and demodulation of signals for telecommunications. For digital signals, signal processing may involve the compression, error detection and error correction of digitally sampled signals.
Telecommunications
Main article: Telecommunications engineering
Telecommunications engineering focuses on the transmission of information across a channel such as a coax cable, optical fibre or free space. Transmissions across free space require information to be encoded in a carrier wave in order to shift the information to a carrier frequency suitable for transmission, this is known as modulation. Popular analog modulation techniques include amplitude modulation and frequency modulation. The choice of modulation affects the cost and performance of a system and these two factors must be balanced carefully by the engineer.
Once the transmission characteristics of a system are determined, telecommunication engineers design the transmitters and receivers needed for such systems. These two are sometimes combined to form a two-way communication device known as a transceiver. A key consideration in the design of transmitters is their power consumption as this is closely related to their signal strength. If the signal strength of a transmitter is insufficient the signal's information will be corrupted by noise.
Instrumentation engineering
Main article: Instrumentation engineering
Instrumentation engineering deals with the design of devices to measure physical quantities such as pressure, flow and temperature. The design of such instrumentation requires a good understanding of physics that often extends beyond electromagnetic theory. For example, radar guns use the Doppler effect to measure the speed of oncoming vehicles. Similarly, thermocouples use the Peltier-Seebeck effect to measure the temperature difference between two points.
Often instrumentation is not used by itself, but instead as the sensors of larger electrical systems. For example, a thermocouple might be used to help ensure a furnace's temperature remains constant. For this reason, instrumentation engineering is often viewed as the counterpart of control engineering.
Computers
Main article: Computer engineering
Computer engineering deals with the design of computers and computer systems. This may involve the design of new hardware, the design of PDAs or the use of computers to control an industrial plant. Computer engineers may also work on a system's software. However, the design of complex software systems is often the domain of software engineering, which is usually considered a separate discipline. Desktop computers represent a tiny fraction of the devices a computer engineer might work on, as computer-like architectures are now found in a range of devices including video game consoles and DVD players.
Related disciplines
Mechatronics is an engineering discipline which deals with the convergence of electrical and mechanical systems. Such combined systems are known as electromechanical systems and have widespread adoption. Examples include automated manufacturing systems, heating, ventilation and air-conditioning systems and various subsystems of aircraft and automobiles.
The term mechatronics is typically used to refer to macroscopic systems but futurists have predicted the emergence of very small electromechanical devices. Already such small devices, known as micro electromechanical systems (MEMS), are used in automobiles to tell airbags when to deploy, in digital projectors to create sharper images and in inkjet printers to create nozzles for high definition printing. In the future it is hoped the devices will help build tiny implantable medical devices and improve optical communication.[31]
Biomedical engineering is another related discipline, concerned with the design of medical equipment. This includes fixed equipment such as ventilators, MRI scanners and electrocardiograph monitors as well as mobile equipment such as cochlear implants, artificial pacemakers and artificial hearts.
See also
Electronics Portal
Engineering Portal
Analog signal processing
Battery charger
Computer engineering
Electronic design automation
Electric motor
Electric vehicle
Electronic engineering
IEEE
Institution of Engineering and Technology (IET)
List of electrical engineering topics (alphabetical)
List of electrical engineering topics (thematic)
List of electrical engineers
Muntzing
Net metering
Plug-in hybrid
V2G
References
^ What is the difference between electrical and electronic engineering?. FAQs - Studying Electrical Engineering. Retrieved on February 4, 2005.
^ William Gilbert (1544–1603). Pioneers in Electricity. Retrieved on May 13, 2007.
^ Vaunt Design Group. (2005).Inventor Alessandro Volta Biography. Troy MI: The Great Idea Finder. Accessed 21 March 2008.
^ ""Ohm, Georg Simon", "Faraday, Michael" and "Maxwell, James Clerk"". Encyclopedia Britannica (11). (1911).
^ Welcome to ECE!. Cornell University - School of Electrical and Computer Engineering. Retrieved on December 29, 2005.
^ Ryder, John and Fink, Donald; (1984). Engineers and Electrons. IEEE Press. ISBN 0-87942-172-X.
^ History. National Fire Protection Association (NFPA). Retrieved on January 19, 2006. (published 1996 in the NFPA Journal)
^ Leland Anderson, "Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony, and Transmission of Power", Sun Publishing Company, LC 92-60482, ISBN 0-9632652-0-2 (ed. excerpts available online)
^ Karl Ferdinand Braun. Retrieved on September 10, 2006.
^ History of Amateur Radio. What is Amateur Radio?. Retrieved on January 18, 2006.
^ Early on, he sent wireless signals over a distance of one and a half miles. In December 1901, he sent wireless waves that were not affected by the curvature of the Earth. Marconi later transmitted the wireless signals across the Atlantic between Poldhu, Cornwall, and St. John's, Newfoundland, a distance of 2100 miles.
^ http://nobelprize.org/nobel_prizes/physics/laureates/1909/marconi-bio.html
^ Albert W. Hull (1880–1966). IEEE History Center. Retrieved on January 22, 2006.
^ Who Invented Microwaves?. Retrieved on January 22, 2006.
^ Early Radar History. Peneley Radar Archives. Retrieved on January 22, 2006.
^ The Z3. Retrieved on January 18, 2006.
^ The ENIAC Museum Online. Retrieved on January 18, 2006.
^ Electronics Timeline. Greatest Engineering Achievements of the Twentieth Century. Retrieved on January 18, 2006.
^ Computing History (1971–1975). Retrieved on January 18, 2006.
^ Various including graduate degree requirements at MIT, study guide at UWA, the curriculum at Queen's and unit tables at Aberdeen
^ Why Should You Get Licensed?. National Society of Professional Engineers. Retrieved on July 11, 2005.
^ Engineers Act. Quebec Statutes and Regulations (CanLII). Retrieved on July 24, 2005.
^ Codes of Ethics and Conduct. Online Ethics Center. Retrieved on July 24, 2005.
^ About the IEEE. IEEE. Retrieved on July 11, 2005.
^ About the IET. The IET. Retrieved on July 11, 2005.
^ Journal and Magazines. The IET. Retrieved on July 11, 2005.
^ Electrical and Electronics Engineers, except Computer. Occupational Outlook Handbook. Retrieved on July 16, 2005. (see here regarding copyright)
^ Science and Engineering Indicators 2004, Appendix 2-33 (PDF). National Science Foundation (2004).
^ Electrical and Electronics Engineers, except Computer. Occupational Outlook Handbook. Retrieved on July 16, 2005. (see Internet Archive)
^ Trevelyan, James; (2005). What Do Engineers Really Do?. University of Western Australia. (seminar with slides)
^ MEMS the world!. IntelliSense Software Corporation. Retrieved on July 17, 2005.
Notes
Note I - There are around 366,000 people working as electrical engineers in the United States constituting 0.25% of the labour force (2002).[1] In Australia, there are around 24,000 constituting 0.23% of the labour force (2005) and in Canada, there are around 34,600 constituting 0.21% of the labour force (2001). Australia and Canada also report that 96% and 89% of their electrical engineers respectively are male.[2][3]
External links
Wikibooks has more on the topic of
Electrical engineering
At Wikiversity you can learn more and teach others about Electrical engineering at:
The Department of Electrical engineering
IEEE Virtual Museum A virtual museum that illustrates many of the basic electrical engineering and electricity concepts through examples, figures, and interviews.
MIT OpenCourseWare In-depth look at Electrical Engineering with online courses featuring video lectures.
Electrical Engineers design power systems...
... and complex electronic circuits.
Electrical engineering — sometimes referred to as electrical and electronic engineering — is an engineering field that deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical power supply. The field now covers a range of sub-studies including power, electronics, control systems, signal processing and telecommunications.
Electrical engineering may or may not encompass electronic engineering. Where a distinction is made, usually outside of the United States, electrical engineering is considered to deal with the problems associated with large-scale electrical systems such as power transmission and motor control, whereas electronic engineering deals with the study of small-scale electronic systems including computers and integrated circuits.[1] Another way of looking at the distinction is that electrical engineers are usually concerned with using electricity to transmit energy, while electronic engineers are concerned with using electricity to transmit information.
Contents
1 History
1.1 Modern developments
2 Education
3 Practicing engineers
4 Tools and work
5 Sub-disciplines
5.1 Power
5.2 Control
5.3 Electronics
5.4 Microelectronics
5.5 Signal processing
5.6 Telecommunications
5.7 Instrumentation engineering
5.8 Computers
6 Related disciplines
7 See also
8 References
9 External links
History
Main article: History of electrical engineering
Electricity has been a subject of scientific interest since at least the early 17th century. The first electrical engineer was probably William Gilbert who designed the versorium: a device that detected the presence of statically charged objects. He was also the first to draw a clear distinction between magnetism and static electricity and is credited with establishing the term electricity.[2] In 1775 Alessandro Volta's scientific experimentations devised the electrophorus, a device that produced a static electric charge, and by 1800 Volta developed the voltaic pile, a forerunner of the electric battery.[3]
However, it was not until the 19th century that research into the subject started to intensify. Notable developments in this century include the work of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor, Michael Faraday, the discoverer of electromagnetic induction in 1831, and James Clerk Maxwell, who in 1873 published a unified theory of electricity and magnetism in his treatise Electricity and Magnetism.[4]
During these years, the study of electricity was largely considered to be a subfield of physics. It was not until the late 19th century that universities started to offer degrees in electrical engineering. The Darmstadt University of Technology founded the first chair and the first faculty of electrical engineering worldwide in 1882. In 1883 Darmstadt University of Technology and Cornell University introduced the world's first courses of study in electrical engineering, and in 1885 the University College London founded the first chair of electrical engineering in the United Kingdom.[5] The University of Missouri subsequently established the first department of electrical engineering in the United States in 1886.[6]
Thomas Edison built the world's first large-scale electrical supply network
During this period, the work concerning electrical engineering increased dramatically. In 1882, Edison switched on the world's first large-scale electrical supply network that provided 110 volts direct current to fifty-nine customers in lower Manhattan. In 1887, Nikola Tesla filed a number of patents related to a competing form of power distribution known as alternating current. In the following years a bitter rivalry between Tesla and Edison, known as the "War of Currents", took place over the preferred method of distribution. AC eventually replaced DC for generation and power distribution, enormously extending the range and improving the safety and efficiency of power distribution.
Nikola Tesla made long-distance electrical transmission networks possible.
The efforts of the two did much to further electrical engineering—Tesla's work on induction motors and polyphase systems influenced the field for years to come, while Edison's work on telegraphy and his development of the stock ticker proved lucrative for his company, which ultimately became General Electric. However, by the end of the 19th century, other key figures in the progress of electrical engineering were beginning to emerge.[7]
Modern developments
Emergence of radio and electronics
During the development of radio, many scientists and inventors contributed to radio technology and electronics. In his classic UHF experiments of 1888, Heinrich Hertz transmitted (via a spark-gap transmitter) and detected radio waves using electrical equipment. In 1895, Nikola Tesla was able to detect signals from the transmissions of his New York lab at West Point (a distance of 80.4 km / 49.95 miles).[8] In 1897, Karl Ferdinand Braun introduced the cathode ray tube as part of an oscilloscope, a crucial enabling technology for electronic television.[9] John Fleming invented the first radio tube, the diode, in 1904. Two years later, Robert von Lieben and Lee De Forest independently developed the amplifier tube, called the triode.[10] In 1895, Guglielmo Marconi furthered the art of hertzian wireless methods.[11][12] In 1920 Albert Hull developed the magnetron which would eventually lead to the development of the microwave oven in 1946 by Percy Spencer.[13][14] In 1934 the British military began to make strides towards radar (which also uses the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station at Bawdsey in August 1936.[15]
In 1941 Konrad Zuse presented the Z3, the world's first fully functional and programmable computer.[16] In 1946 the ENIAC (Electronic Numerical Integrator and Computer) of John Presper Eckert and John Mauchly followed, beginning the computing era. The arithmetic performance of these machines allowed engineers to develop completely new technologies and achieve new objectives, including the Apollo missions and the NASA moon landing.[17]
The invention of the transistor in 1947 by William B. Shockley, John Bardeen and Walter Brattain opened the door for more compact devices and led to the development of the integrated circuit in 1958 by Jack Kilby and independently in 1959 by Robert Noyce.[18] In 1968 Marcian Hoff invented the first microprocessor at Intel and thus ignited the development of the personal computer. The first realization of the microprocessor was the Intel 4004, a 4-bit processor developed in 1971, but only in 1973 did the Intel 8080, an 8-bit processor, make the building of the first personal computer, the Altair 8800, possible.[19]
Education
Electrical engineers typically possess an academic degree with a major in electrical engineering. The length of study for such a degree is usually four or five years and the completed degree may be designated as a Bachelor of Engineering, Bachelor of Science, Bachelor of Technology or Bachelor of Applied Science depending upon the university. The degree generally includes units covering physics, mathematics, computer science, project management and specific topics in electrical engineering. Initially such topics cover most, if not all, of the sub-disciplines of electrical engineering. Students then choose to specialize in one or more sub-disciplines towards the end of the degree.
Some electrical engineers also choose to pursue a postgraduate degree such as a Master of Engineering/Master of Science (MEng/MSc), a Master of Engineering Management, a Doctor of Philosophy (PhD) in Engineering, an Engineering Doctorate (EngD), or an Engineer's degree. The Master and Engineer's degree may consist of either research, coursework or a mixture of the two. The Doctor of Philosophy and Engineering Doctorate degrees consist of a significant research component and are often viewed as the entry point to academia. In the United Kingdom and various other European countries, the Master of Engineering is often considered an undergraduate degree of slightly longer duration than the Bachelor of Engineering.[20]
Practicing engineers
In most countries, a Bachelor's degree in engineering represents the first step towards professional certification and the degree program itself is certified by a professional body. After completing a certified degree program the engineer must satisfy a range of requirements (including work experience requirements) before being certified. Once certified the engineer is designated the title of Professional Engineer (in the United States, Canada and South Africa ), Chartered Engineer (in India, the United Kingdom, Ireland and Zimbabwe), Chartered Professional Engineer (in Australia and New Zealand) or European Engineer (in much of the European Union).
The advantages of certification vary depending upon location. For example, in the United States and Canada "only a licensed engineer may seal engineering work for public and private clients".[21] This requirement is enforced by state and provincial legislation such as Quebec's Engineers Act.[22] In other countries, such as Australia, no such legislation exists. Practically all certifying bodies maintain a code of ethics that they expect all members to abide by or risk expulsion.[23] In this way these organizations play an important role in maintaining ethical standards for the profession. Even in jurisdictions where certification has little or no legal bearing on work, engineers are subject to contract law. In cases where an engineer's work fails he or she may be subject to the tort of negligence and, in extreme cases, the charge of criminal negligence. An engineer's work must also comply with numerous other rules and regulations such as building codes and legislation pertaining to environmental law.
Professional bodies of note for electrical engineers include the Institute of Electrical and Electronics Engineers (IEEE) and the Institution of Engineering and Technology (IET) (which was formed by the merging of the Institution of Electrical Engineers (IEE) and the Institution of Incorporated Engineers (IIE). The IEEE claims to produce 30% of the world's literature in electrical engineering, has over 360,000 members worldwide and holds over 3,000 conferences annually.[24] The IET publishes 21 journals, has a worldwide membership of over 150,000, and claims to be the largest professional engineering society in Europe.[25][26] Obsolescence of technical skills is a serious concern for electrical engineers. Membership and participation in technical societies, regular reviews of periodicals in the field and a habit of continued learning are therefore essential to maintaining proficiency.[27]
In countries such as Australia, Canada and the United States electrical engineers make up around 0.25% of the labor force (see note). Outside of these countries, it is difficult to gauge the demographics of the profession due to less meticulous reporting on labour statistics. However, in terms of electrical engineering graduates per-capita, electrical engineering graduates would probably be most numerous in countries such as Taiwan, Japan, India and South Korea.[28]
Tools and work
From the Global Positioning System to electric power generation, electrical engineers have contributed to the development of a wide range of technologies. They design, develop, test and supervise the deployment of electrical systems and electronic devices. For example, they may work on the design of telecommunication systems, the operation of electric power stations, the lighting and wiring of buildings, the design of household appliances or the electrical control of industrial machinery.[29]
Satellite communications is one of many projects an electrical engineer might work on
Fundamental to the discipline are the sciences of physics and mathematics as these help to obtain both a qualitative and quantitative description of how such systems will work. Today most engineering work involves the use of computers and it is commonplace to use computer-aided design programs when designing electrical systems. Nevertheless, the ability to sketch ideas is still invaluable for quickly communicating with others.
Although most electrical engineers will understand basic circuit theory (that is the interactions of elements such as resistors, capacitors, diodes, transistors and inductors in a circuit), the theories employed by engineers generally depend upon the work they do. For example, quantum mechanics and solid state physics might be relevant to an engineer working on VLSI (the design of integrated circuits), but are largely irrelevant to engineers working with macroscopic electrical systems. Even circuit theory may not be relevant to a person designing telecommunication systems that use off-the-shelf components. Perhaps the most important technical skills for electrical engineers are reflected in university programs, which emphasize strong numerical skills, computer literacy and the ability to understand the technical language and concepts that relate to electrical engineering.
For many engineers, technical work accounts for only a fraction of the work they do. A lot of time may also be spent on tasks such as discussing proposals with clients, preparing budgets and determining project schedules.[30] Many senior engineers manage a team of technicians or other engineers and for this reason project management skills are important. Most engineering projects involve some form of documentation and strong written communication skills are therefore very important.
The workplaces of electrical engineers are just as varied as the types of work they do. Electrical engineers may be found in the pristine lab environment of a fabrication plant, the offices of a consulting firm or on site at a mine. During their working life, electrical engineers may find themselves supervising a wide range of individuals including scientists, electricians, computer programmers and other engineers.
Sub-disciplines
Electrical engineering has many sub-disciplines, the most popular of which are listed below. Although there are electrical engineers who focus exclusively on one of these sub-disciplines, many deal with a combination of them. Sometimes certain fields, such as electronic engineering and computer engineering, are considered separate disciplines in their own right.
Power
Main article: Power engineering
Power engineering deals with the generation, transmission and distribution of electricity as well as the design of a range of related devices. These include transformers, electric generators, electric motors, high voltage engineering and power electronics. In many regions of the world, governments maintain an electrical network called a power grid that connects a variety of generators together with users of their energy. Users purchase electrical energy from the grid, avoiding the costly exercise of having to generate their own. Power engineers may work on the design and maintenance of the power grid as well as the power systems that connect to it. Such systems are called on-grid power systems and may supply the grid with additional power, draw power from the grid or do both. Power engineers may also work on systems that do not connect to the grid, called off-grid power systems, which in some cases are preferable to on-grid systems. The future includes Satellite controlled power systems, with feedback in real time to prevent power surges and prevent blackouts.
Control
Main article: Control engineering
Control engineering focuses on the modeling of a diverse range of dynamic systems and the design of controllers that will cause these systems to behave in the desired manner. To implement such controllers electrical engineers may use electrical circuits, digital signal processors, microcontrollers and PLCs (Programmable Logic Controllers). Control engineering has a wide range of applications from the flight and propulsion systems of commercial airliners to the cruise control present in many modern automobiles. It also plays an important role in industrial automation.
Control engineers often utilize feedback when designing control systems. For example, in an automobile with cruise control the vehicle's speed is continuously monitored and fed back to the system which adjusts the motor's power output accordingly. Where there is regular feedback, control theory can be used to determine how the system responds to such feedback.
Electronics
Main article: Electronic engineering
Electronic engineering involves the design and testing of electronic circuits that use the properties of components such as resistors, capacitors, inductors, diodes and transistors to achieve a particular functionality. The tuned circuit, which allows the user of a radio to filter out all but a single station, is just one example of such a circuit. Another example (of a pneumatic signal conditioner) is shown in the adjacent photograph.
Prior to the second world war, the subject was commonly known as radio engineering and basically was restricted to aspects of communications and radar, commercial radio and early television. Later, in post war years, as consumer devices began to be developed, the field grew to include modern television, audio systems, computers and microprocessors. In the mid to late 1950s, the term radio engineering gradually gave way to the name electronic engineering.
Before the invention of the integrated circuit in 1959, electronic circuits were constructed from discrete components that could be manipulated by humans. These discrete circuits consumed much space and power and were limited in speed, although they are still common in some applications. By contrast, integrated circuits packed a large number—often millions—of tiny electrical components, mainly transistors, into a small chip around the size of a coin. This allowed for the powerful computers and other electronic devices we see today.
Microelectronics
Main article: Microelectronics
Microelectronics engineering deals with the design of very small electronic circuit components for use in an integrated circuit or sometimes for use on their own as a general electronic component. The most common microelectronic components are semiconductor transistors, although all main electronic components (resistors, capacitors, inductors) can be created at a microscopic level.
Microelectronic components are created by chemically fabricating wafers of semiconductors such as silicon (at higher frequencies, compound semiconductors like gallium arsenide and indium phosphide) to obtain the desired transport of electronic charge and control of current. The field of microelectronics involves a significant amount of chemistry and material science and requires the electronic engineer working in the field to have a very good working knowledge of the effects of quantum mechanics.
Signal processing
A Bayer filter on a CCD requires signal processing to get a red, green, and blue value at each pixel
Main article: Signal processing
Signal processing deals with the analysis and manipulations of signals. Signals can be either analog, in which case the signal varies continuously according to the information, or digital, in which case the signal varies according to a series of discrete values representing the information. For analog signals, signal processing may involve the amplification and filtering of audio signals for audio equipment or the modulation and demodulation of signals for telecommunications. For digital signals, signal processing may involve the compression, error detection and error correction of digitally sampled signals.
Telecommunications
Main article: Telecommunications engineering
Telecommunications engineering focuses on the transmission of information across a channel such as a coax cable, optical fibre or free space. Transmissions across free space require information to be encoded in a carrier wave in order to shift the information to a carrier frequency suitable for transmission, this is known as modulation. Popular analog modulation techniques include amplitude modulation and frequency modulation. The choice of modulation affects the cost and performance of a system and these two factors must be balanced carefully by the engineer.
Once the transmission characteristics of a system are determined, telecommunication engineers design the transmitters and receivers needed for such systems. These two are sometimes combined to form a two-way communication device known as a transceiver. A key consideration in the design of transmitters is their power consumption as this is closely related to their signal strength. If the signal strength of a transmitter is insufficient the signal's information will be corrupted by noise.
Instrumentation engineering
Main article: Instrumentation engineering
Instrumentation engineering deals with the design of devices to measure physical quantities such as pressure, flow and temperature. The design of such instrumentation requires a good understanding of physics that often extends beyond electromagnetic theory. For example, radar guns use the Doppler effect to measure the speed of oncoming vehicles. Similarly, thermocouples use the Peltier-Seebeck effect to measure the temperature difference between two points.
Often instrumentation is not used by itself, but instead as the sensors of larger electrical systems. For example, a thermocouple might be used to help ensure a furnace's temperature remains constant. For this reason, instrumentation engineering is often viewed as the counterpart of control engineering.
Computers
Main article: Computer engineering
Computer engineering deals with the design of computers and computer systems. This may involve the design of new hardware, the design of PDAs or the use of computers to control an industrial plant. Computer engineers may also work on a system's software. However, the design of complex software systems is often the domain of software engineering, which is usually considered a separate discipline. Desktop computers represent a tiny fraction of the devices a computer engineer might work on, as computer-like architectures are now found in a range of devices including video game consoles and DVD players.
Related disciplines
Mechatronics is an engineering discipline which deals with the convergence of electrical and mechanical systems. Such combined systems are known as electromechanical systems and have widespread adoption. Examples include automated manufacturing systems, heating, ventilation and air-conditioning systems and various subsystems of aircraft and automobiles.
The term mechatronics is typically used to refer to macroscopic systems but futurists have predicted the emergence of very small electromechanical devices. Already such small devices, known as micro electromechanical systems (MEMS), are used in automobiles to tell airbags when to deploy, in digital projectors to create sharper images and in inkjet printers to create nozzles for high definition printing. In the future it is hoped the devices will help build tiny implantable medical devices and improve optical communication.[31]
Biomedical engineering is another related discipline, concerned with the design of medical equipment. This includes fixed equipment such as ventilators, MRI scanners and electrocardiograph monitors as well as mobile equipment such as cochlear implants, artificial pacemakers and artificial hearts.
See also
Electronics Portal
Engineering Portal
Analog signal processing
Battery charger
Computer engineering
Electronic design automation
Electric motor
Electric vehicle
Electronic engineering
IEEE
Institution of Engineering and Technology (IET)
List of electrical engineering topics (alphabetical)
List of electrical engineering topics (thematic)
List of electrical engineers
Muntzing
Net metering
Plug-in hybrid
V2G
References
^ What is the difference between electrical and electronic engineering?. FAQs - Studying Electrical Engineering. Retrieved on February 4, 2005.
^ William Gilbert (1544–1603). Pioneers in Electricity. Retrieved on May 13, 2007.
^ Vaunt Design Group. (2005).Inventor Alessandro Volta Biography. Troy MI: The Great Idea Finder. Accessed 21 March 2008.
^ ""Ohm, Georg Simon", "Faraday, Michael" and "Maxwell, James Clerk"". Encyclopedia Britannica (11). (1911).
^ Welcome to ECE!. Cornell University - School of Electrical and Computer Engineering. Retrieved on December 29, 2005.
^ Ryder, John and Fink, Donald; (1984). Engineers and Electrons. IEEE Press. ISBN 0-87942-172-X.
^ History. National Fire Protection Association (NFPA). Retrieved on January 19, 2006. (published 1996 in the NFPA Journal)
^ Leland Anderson, "Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony, and Transmission of Power", Sun Publishing Company, LC 92-60482, ISBN 0-9632652-0-2 (ed. excerpts available online)
^ Karl Ferdinand Braun. Retrieved on September 10, 2006.
^ History of Amateur Radio. What is Amateur Radio?. Retrieved on January 18, 2006.
^ Early on, he sent wireless signals over a distance of one and a half miles. In December 1901, he sent wireless waves that were not affected by the curvature of the Earth. Marconi later transmitted the wireless signals across the Atlantic between Poldhu, Cornwall, and St. John's, Newfoundland, a distance of 2100 miles.
^ http://nobelprize.org/nobel_prizes/physics/laureates/1909/marconi-bio.html
^ Albert W. Hull (1880–1966). IEEE History Center. Retrieved on January 22, 2006.
^ Who Invented Microwaves?. Retrieved on January 22, 2006.
^ Early Radar History. Peneley Radar Archives. Retrieved on January 22, 2006.
^ The Z3. Retrieved on January 18, 2006.
^ The ENIAC Museum Online. Retrieved on January 18, 2006.
^ Electronics Timeline. Greatest Engineering Achievements of the Twentieth Century. Retrieved on January 18, 2006.
^ Computing History (1971–1975). Retrieved on January 18, 2006.
^ Various including graduate degree requirements at MIT, study guide at UWA, the curriculum at Queen's and unit tables at Aberdeen
^ Why Should You Get Licensed?. National Society of Professional Engineers. Retrieved on July 11, 2005.
^ Engineers Act. Quebec Statutes and Regulations (CanLII). Retrieved on July 24, 2005.
^ Codes of Ethics and Conduct. Online Ethics Center. Retrieved on July 24, 2005.
^ About the IEEE. IEEE. Retrieved on July 11, 2005.
^ About the IET. The IET. Retrieved on July 11, 2005.
^ Journal and Magazines. The IET. Retrieved on July 11, 2005.
^ Electrical and Electronics Engineers, except Computer. Occupational Outlook Handbook. Retrieved on July 16, 2005. (see here regarding copyright)
^ Science and Engineering Indicators 2004, Appendix 2-33 (PDF). National Science Foundation (2004).
^ Electrical and Electronics Engineers, except Computer. Occupational Outlook Handbook. Retrieved on July 16, 2005. (see Internet Archive)
^ Trevelyan, James; (2005). What Do Engineers Really Do?. University of Western Australia. (seminar with slides)
^ MEMS the world!. IntelliSense Software Corporation. Retrieved on July 17, 2005.
Notes
Note I - There are around 366,000 people working as electrical engineers in the United States constituting 0.25% of the labour force (2002).[1] In Australia, there are around 24,000 constituting 0.23% of the labour force (2005) and in Canada, there are around 34,600 constituting 0.21% of the labour force (2001). Australia and Canada also report that 96% and 89% of their electrical engineers respectively are male.[2][3]
External links
Wikibooks has more on the topic of
Electrical engineering
At Wikiversity you can learn more and teach others about Electrical engineering at:
The Department of Electrical engineering
IEEE Virtual Museum A virtual museum that illustrates many of the basic electrical engineering and electricity concepts through examples, figures, and interviews.
MIT OpenCourseWare In-depth look at Electrical Engineering with online courses featuring video lectures.
Electronic waste
Electronic waste
This article needs additional citations for verification.Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (November 2007)
The introduction of this article is too short.To comply with Wikipedia's lead section guidelines, it should be expanded to summarize the article.
Electronic waste, "e-waste" or "Waste Electrical and Electronic Equipment" ("WEEE") is a waste type consisting of any broken or unwanted electrical or electronic appliance. Recyclable electronic waste is sometimes further categorized as a "commodity" while e-waste which cannot be reused is distinguished as "waste". Both types of e-waste have raised concern considering that many components of such equipment are considered toxic and are not biodegradable. Responding to these concerns, many European countries banned e-waste from landfills in the 1990s.
The European Union would further advance e-waste policy in Europe by implementing the Waste Electrical and Electronic Equipment Directive in 2002 which holds manufacturers responsible for e-waste disposal at end-of-life. Similar legislation has been enacted in Asia, with e-waste legislation in the United States limited to the state level due to stalled efforts in the United States Congress regarding multiple e-waste legislation bills.
Due to the difficulty and cost of recycling used electronics as well as lacklustre enforcement of legislation regarding e-waste exports, large amounts of used electronics have been sent to countries such as China, India, and Kenya, where lower environmental standards and working conditions make processing e-waste more profitable.[1]
Contents
1 Definition
2 Problems
3 Trends in disposal and recycling
4 List of substances contained in electronic waste
4.1 Substances in bulk
4.2 Elements in bulk
4.3 Elements in small amounts
4.4 Elements in trace amounts (alphabetical)
4.5 List of example applications of the above elements and substances
5 See also
6 References
7 External links
Definition
Some activists define "Electronic waste" to include all secondary computers, entertainment devices electronics, mobile phones and other items, whether they have been sold, donated, or discarded by their original owner. This definition includes used electronics which are destined for reuse, resale, salvage, recycling or disposal. Others define the reusable (working and repairable electronics) and secondary scrap (copper, steel, plastic, etc.) to be "commodities", and reserve the use of the term "waste" for residue or material which was represented as working or repairable but which was discarded by the buyer.
Debate continues over the distinction between "commodity" and "waste" electronics definitions. Some exporters may deliberately leave obsolete or non-working equipment mixed in loads of working equipment (through ignorance, or to avoid more costly treatment processes for 'bad' equipment). On the other hand, some importing countries specifically seek to exclude working or repairable equipment in order to protect domestic manufacturing markets. "White box" computers ('off-brand' or 'no name' computers) are often assembled by smaller scale manufacturers utilizing refurbished components. These 'white box' sales accounted for approximately 45% of all computer sales worldwide by 2004, and are considered a threat to some large manufacturers, who therefore seek to classify used computers as 'waste'.
While a protectionist may broaden the definition of "waste" electronics, the high value of working and reusable laptops, computers, and components (e.g. RAM), can help pay the cost of transportation for a large number of worthless "commodities". Broken monitors, obsolete circuit boards, short circuited transistors, and other junk are difficult to spot in a containerload of used electronics.
Until such time as equipment no longer contains such hazardous substances, the disposal and recycling operations must be undertaken with great care to avoid damaging pollution and workplace hazards, and exports need to be monitored to avoid "toxics along for the ride".
Problems
If treated properly, electronic waste is a valuable source for secondary raw materials. However, if not treated properly, it is a major source of toxins and carcinogens. Rapid technology change, low initial cost and even planned obsolescence have resulted in a fast growing problem around the globe. Technical solutions are available but in most cases a legal framework, a collection system, logistics and other services need to be implemented before a technical solution can be applied. Electronic waste represents 2 percent of America's trash in landfills, but it equals 70 percent of overall toxic waste.[2]
Due to lower environmental standards and working conditions in China, India, Kenya, and elsewhere, electronic waste is being sent to these countries for processing – in most cases illegally. Guiyu in Shantou region of China, and Delhi and Bangalore in India, all have electronic waste processing areas.[3] Uncontrolled burning, disassembly, and disposal are causing environmental and health problems, including occupational safety and health effects among those directly involved, due to the methods of processing the waste. Trade in electronic waste is controlled by the Basel Convention.
Electronic waste is of concern largely due to the toxicity and carcinogenicity of some of the substances if processed improperly. Toxic substances in electronic waste may include lead, mercury, cadmium. Carcinogenic substances in electronic waste may include polychlorinated biphenyls (PCBs). A typical computer monitor may contain more than 6% lead by weight, much of which is in the lead glass of the CRT. Capacitors, transformers, PVC insulated wires, PVC coated components that were manufactured before 1977 often contain dangerous amounts of polychlorinated biphenyls.[4] Up to thirty-eight separate chemical elements are incorporated into electronic waste items. The unsustainability of discarding electronics and computer technology is another reason for the need to recycle – or perhaps more practically, reuse – electronic waste.
E-waste is often exported to developing countries
Electronic waste processing systems have matured in recent years following increased regulatory, public, and commercial scrutiny, and a commensurate increase in entrepreneurial interest. Part of this evolution has involved greater diversion of electronic waste from energy intensive, down-cycling processes (eg. conventional recycling) where equipment is reverted to a raw material form. This diversion is achieved through reuse and refurbishing. The environmental and social benefits of reuse are several: diminished demand for new products and their commensurate requirement for virgin raw materials (with their own environmental externalities not factored into the cost of the raw materials) and larger quantities of pure water and electricity for associated manufacturing, less packaging per unit, availability of technology to wider swaths of society due to greater affordability of products, and diminished use of landfills.
Challenges remain, when materials cannot or will not be reused, conventional recycling or disposal via landfill often follow. Standards for both approaches vary widely by jurisdiction, whether in developed or developing countries. The complexity of the various items to be disposed of, cost of environmentally sound recycling systems, and the need for concerned and concerted action to collect and systematically process equipment are the resources most lacked -- though this is changing. Many of the plastics used in electronic equipment contain flame retardants. These are generally halogens added to the plastic resin, making the plastics difficult to recycle.
Trends in disposal and recycling
WEEE Man
In the 1990s some European countries banned the disposal of electronic waste in landfills. This created an e-waste processing industry in Europe.
In Switzerland the first electronic waste recycling system was implemented in 1991 beginning with collection of old refrigerators. Over the years, all other electric and electronic devices were gradually added to the system. Legislation followed in 1998 and since January 2005 it has been possible to return all electronic waste to the sales points and other collection points free of charge. There are two established PROs (Producer Responsibility Organizations): SWICO mainly handling electronic waste and SENS mainly responsible for electrical appliances. The total amount of recycled electronic waste exceeds 10 kg per capita per year.[5][6][7]
The European Union has implemented a similar system under the Waste Electrical and Electronic Equipment Directive (WEEE 2002/96/EC). The WEEE Directive has now been transposed in national laws in all member countries of the European Union. The WEEE directive was designed to make equipment manufacturers financially or physically responsible for their equipment at its end-of-life under a policy known as extended producer responsibility (EPR). EPR was seen as a useful policy as it internalized the end-of-life costs and provided a competitive incentive for companies to design equipment with less costs and liabilities when it reached its end-of-life. However the application of the WEEE directive has been criticized for implementing the EPR concept in a collective manner and thereby losing the competitive incentive of individual manufacturers to be rewarded for their green design.[8] Since 13 August 2005, the electronics manufacturers became financially responsible for compliance to the WEEE directive. Under the directive, by the end of 2006 – and with one or two years' delay for the new EU members – every country has to recycle at least 4 kg of e-waste per capita per year.
Some states in recent years in the US developed policies banning CRTs from landfills due to the fear that the heavy metals contained in the glass would eventually leach into groundwater. Circuit boards also contain considerable quantities of lead-tin solders and are even more likely to leach into groundwater or become air pollution if managed in an incinerator. Indeed, a policy of "diversion from landfill" has been the driver for legislation in many states requiring higher and higher volumes of e-waste to be collected and processed separate from the solid waste stream. Today the e-waste recycling business is in all areas of the developed world a big and rapidly consolidating business. Unfortunately, increased regulation of e-waste and concern over the environmental harm which can result from toxic e-waste has raised disposal costs. This has had the unforeseen effect of providing brokers and others calling themselves recyclers with an incentive to export the e-waste to developing countries. This form of toxic trade was first exposed by the Basel Action Network (BAN) in their 2002 report and film entitled "Exporting Harm: The High-Tech Trashing of Asia".[9] Exporting Harm placed a spotlight on the global dumping of electronic waste, primarily from North America on a township area of China known as Guiyu. To this day in Guiyu, thousands of men, women and children are employed, in highly polluting, primitive recycling technologies, extracting the metals, toners, and plastics from computers and other e-waste. Because the United States has not ratified the Basel Convention or the Basel Ban Amendment, and has no domestic laws forbidding the export of toxic waste, BAN estimates that about 80% of the e-waste directed to recycling in the US does not get recycled there at all but is put on container ships and sent to countries such as China.[10][3] High Tech Trash: Digital Devices, Hidden Toxics, and Human Health by Elizabeth Grossman [Island Press, 2006, 2007.]
In developed countries, e-waste processing usually first involves dismantling the equipment into various parts — metal frames, power supplies, circuit boards, and plastics — which are separated, often by hand. Alternatively, material is shredded, and sophisticated expensive equipment separates the various metal and plastic fractions, which then are sold to various smelters and or plastics recyclers. From 2004 the state of California introduced a Electronic Waste Recycling Fee on all new monitors and televisions sold to cover the cost of recycling. The amount of the fee depends on the size of the monitor. That amount was adjusted on July 1, 2005 in order to match the real cost of recycling. Canada has also begun to take responsibility for electronics recycling. For example, in August of 2007 a fee similar to the one in California was added to the cost of purchasing new televisions, computers, and computer components in British Columbia. The new legislation made recycling mandatory for all of those products.
A typical electronic waste recycling plant as found in some industrialized countries combines the best of dismantling for component recovery with increased capacity to process large amounts of electronic waste in a cost effective-manner. Material is fed into a hopper, which travels up a conveyor and is dropped into the mechanical separator, which is followed by a number of screening and granulating machines. The entire recycling machinery is enclosed and employs a dust collection system. The European Union, South Korea, Japan and Taiwan have already demanded that sellers and manufacturers of electronics be responsible for recycling 75% of them.
Many Asian countries have legislated, or will do so, for electronic waste recycling.
The United States Congress is considering a number of electronic waste bills including the National Computer Recycling Act introduced by Congressman Mike Thompson (D-CA). This bill has continually stalled, however.
In the meantime, several states have passed their own laws regarding electronic waste management. California was the first state to enact such legislation, followed by Maryland, Maine, Washington and Minnesota. More recently, legislatures in Oregon and Texas passed their own laws.
List of substances contained in electronic waste
Substances in bulk
Polychlorinated biphenyls (PCBs), polyvinyl chloride (PVC), thermosetting plastics, epoxy resins, and fibre glass.
Elements in bulk
Lead, tin, copper, silicon, beryllium, carbon, iron and aluminium
Elements in small amounts
Cadmium, mercury, thallium[11]
Elements in trace amounts (alphabetical)
Americium, antimony, arsenic, barium, bismuth, boron, cobalt, europium, gallium, germanium, gold, indium, lithium, manganese, nickel, niobium, palladium, platinum, rhodium, ruthenium, selenium, silver, tantalum, terbium, thorium, titanium, vanadium, and yttrium.
List of example applications of the above elements and substances
Almost all electronics contain lead and tin (as solder) and copper (as wire and PCB tracks), though the use of lead-free solder is now spreading rapidly.
Lead: solder, CRT monitors (lead in glass), lead-acid batteries
Tin: solder, coatings on component leads
Copper: copper wire, printed circuit board tracks, component leads
Cadmium: light-sensitive resistors, corrosion-resistant alloys for marine and aviation environments
Aluminium: nearly all electronic goods using more than a few watts of power (heatsinks), electrolytic capacitors.
Beryllium oxide: filler in some thermal interface materials such as thermal grease used on heatsinks for CPUs and power transistors,[12] magnetrons, X-ray-transparent ceramic windows, heat transfer fins in vacuum tubes, and gas lasers.
Iron: steel chassis, cases and fixings
Silicon: glass, transistors, ICs, printed circuit boards.
Nickel and cadmium: nickel-cadmium batteries
Lithium: lithium-ion battery
Zinc: plating for steel parts
Gold: connector plating, primarily in computer equipment
Americium: smoke alarms (radioactive source)
Germanium: 1950s–1960s transistorised electronics (bipolar junction transistors)
Mercury: fluorescent tubes (numerous applications), tilt switches (pinball games, mechanical doorbells, thermostats)
Sulphur: lead-acid batteries
Carbon: steel, plastics, resistors. In almost all electronic equipment.
Polychlorinated biphenyls (PCBs) (prior to ban): in almost all 1930s–1970s equipment including capacitors, transformers, wiring insulation, paints, inks, and flexible sealants
See also
Electronics Portal
Waste Electrical and Electronic Equipment Directive
Electronic Waste Recycling Act
Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal
Digger gold
Electronic Waste Recycling Fee
Free Geek - recycling and re-using computer equipment based on the 'Free to all' philosophy.
Green computing
Polychlorinated biphenyls - see Handling Procedures
Solving the E-waste Problem or StEP
RoHS
Computer recycling
Silicon valley toxics coalition
References
^ Where does all the e-waste go? Greenpeace International
^ Slade, Giles. "iWaste", Mother Jones, 2007-04-01. Retrieved on 2007-04-03.
^ BAN and SVTC. 2002. "Exporting Harm: The High-Tech Trashing of Asia". Seattle and San Jose: Basel Action Network and Silicon Valley Toxics Coalition, February 25, 2002. Available: http://www.ban.org/E-waste/technotrashfinalcomp.pdf
^ Karlyn Black Kaley, Jim Carlisle, David Siegel, Julio Salinas (October 2006). Health Concerns and Environmental Issues with PVC-Containing Building Materials in Green Buildings (pdf), Integrated Waste Management Board, California Environmental Protection Agency, USA, p.11. Retrieved on 2007-08-03.
^ Umwelt Schweiz, Accessed 24.11.06
^ Swico, Accessed 24.11.06
^ SENS, Accessed 24.11.06
^ Lost In Transposition?, Greenpeace Report, 27 September 2006, [1]
^ "High-Tech Trash", National Geographic Magazine, January 2008. [2]
^ America Ships Electronic Waste Overseas By Terence Chea, Associated Press, 11/18/07.
^ Chemical fact sheet — Thallium. Spectrum Laboratories. Retrieved on 2008-02-02.
^ Greg Becker, Chris Lee, and Zuchen Lin (Jul 2005). "Thermal conductivity in advanced chips — Emerging generation of thermal greases offers advantages". Advanced Packaging: pp.2-4. Retrieved on 2008-03-04.
^High Tech Trash: Digital Devices, Hidden Toxics, and Human Health by Elizabeth Grossman (Island Press, 2006, 2007) ^Where Computers Go to Die....And Kill by Elizabeth Grossman, Salon, April 2006
External links
The external links in this article may not follow Wikipedia's content policies or guidelines.Please improve this article by removing excessive or inappropriate external links.
The Secret Life of Cell Phonesan INFORM, Inc. Video Project
e-Waste Guide A knowledge base for the sustainable recycling of e-Waste
Indian e-Waste Guide A knowledge base for the sustainable recycling of e-Waste specific to India
European Commission WEEE page
RoHS directive (PDF)
WEEE directive (PDF)
US EPA's 'eCycling' Program
Inside the Digital Dump, a photoessay from Foreign Policy Magazine
BBC Article "Gadget recycling foxes consumers"
The Electronic Waste Problem
Greenpeace Electronic Waste Campaign
Greener Computing - covers eWaste and other green computing issues
Recent 'bust' illuminates underground electronics export business in Canada Canada.com accessed December 22, 2006
WEEE was not thought through
The e-waste problem in China
[hide]
v • d • e
Topics related to waste management
Anaerobic digestion · Composting · Eco-industrial park · Incineration · Landfill · Mechanical biological treatment · Radioactive waste · Reuse · Recycling · Regiving · Sewerage · Waste · Waste collection · Waste sorting · Waste hierarchy · Waste management concepts · Waste legislation · Waste treatment
This article needs additional citations for verification.Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (November 2007)
The introduction of this article is too short.To comply with Wikipedia's lead section guidelines, it should be expanded to summarize the article.
Electronic waste, "e-waste" or "Waste Electrical and Electronic Equipment" ("WEEE") is a waste type consisting of any broken or unwanted electrical or electronic appliance. Recyclable electronic waste is sometimes further categorized as a "commodity" while e-waste which cannot be reused is distinguished as "waste". Both types of e-waste have raised concern considering that many components of such equipment are considered toxic and are not biodegradable. Responding to these concerns, many European countries banned e-waste from landfills in the 1990s.
The European Union would further advance e-waste policy in Europe by implementing the Waste Electrical and Electronic Equipment Directive in 2002 which holds manufacturers responsible for e-waste disposal at end-of-life. Similar legislation has been enacted in Asia, with e-waste legislation in the United States limited to the state level due to stalled efforts in the United States Congress regarding multiple e-waste legislation bills.
Due to the difficulty and cost of recycling used electronics as well as lacklustre enforcement of legislation regarding e-waste exports, large amounts of used electronics have been sent to countries such as China, India, and Kenya, where lower environmental standards and working conditions make processing e-waste more profitable.[1]
Contents
1 Definition
2 Problems
3 Trends in disposal and recycling
4 List of substances contained in electronic waste
4.1 Substances in bulk
4.2 Elements in bulk
4.3 Elements in small amounts
4.4 Elements in trace amounts (alphabetical)
4.5 List of example applications of the above elements and substances
5 See also
6 References
7 External links
Definition
Some activists define "Electronic waste" to include all secondary computers, entertainment devices electronics, mobile phones and other items, whether they have been sold, donated, or discarded by their original owner. This definition includes used electronics which are destined for reuse, resale, salvage, recycling or disposal. Others define the reusable (working and repairable electronics) and secondary scrap (copper, steel, plastic, etc.) to be "commodities", and reserve the use of the term "waste" for residue or material which was represented as working or repairable but which was discarded by the buyer.
Debate continues over the distinction between "commodity" and "waste" electronics definitions. Some exporters may deliberately leave obsolete or non-working equipment mixed in loads of working equipment (through ignorance, or to avoid more costly treatment processes for 'bad' equipment). On the other hand, some importing countries specifically seek to exclude working or repairable equipment in order to protect domestic manufacturing markets. "White box" computers ('off-brand' or 'no name' computers) are often assembled by smaller scale manufacturers utilizing refurbished components. These 'white box' sales accounted for approximately 45% of all computer sales worldwide by 2004, and are considered a threat to some large manufacturers, who therefore seek to classify used computers as 'waste'.
While a protectionist may broaden the definition of "waste" electronics, the high value of working and reusable laptops, computers, and components (e.g. RAM), can help pay the cost of transportation for a large number of worthless "commodities". Broken monitors, obsolete circuit boards, short circuited transistors, and other junk are difficult to spot in a containerload of used electronics.
Until such time as equipment no longer contains such hazardous substances, the disposal and recycling operations must be undertaken with great care to avoid damaging pollution and workplace hazards, and exports need to be monitored to avoid "toxics along for the ride".
Problems
If treated properly, electronic waste is a valuable source for secondary raw materials. However, if not treated properly, it is a major source of toxins and carcinogens. Rapid technology change, low initial cost and even planned obsolescence have resulted in a fast growing problem around the globe. Technical solutions are available but in most cases a legal framework, a collection system, logistics and other services need to be implemented before a technical solution can be applied. Electronic waste represents 2 percent of America's trash in landfills, but it equals 70 percent of overall toxic waste.[2]
Due to lower environmental standards and working conditions in China, India, Kenya, and elsewhere, electronic waste is being sent to these countries for processing – in most cases illegally. Guiyu in Shantou region of China, and Delhi and Bangalore in India, all have electronic waste processing areas.[3] Uncontrolled burning, disassembly, and disposal are causing environmental and health problems, including occupational safety and health effects among those directly involved, due to the methods of processing the waste. Trade in electronic waste is controlled by the Basel Convention.
Electronic waste is of concern largely due to the toxicity and carcinogenicity of some of the substances if processed improperly. Toxic substances in electronic waste may include lead, mercury, cadmium. Carcinogenic substances in electronic waste may include polychlorinated biphenyls (PCBs). A typical computer monitor may contain more than 6% lead by weight, much of which is in the lead glass of the CRT. Capacitors, transformers, PVC insulated wires, PVC coated components that were manufactured before 1977 often contain dangerous amounts of polychlorinated biphenyls.[4] Up to thirty-eight separate chemical elements are incorporated into electronic waste items. The unsustainability of discarding electronics and computer technology is another reason for the need to recycle – or perhaps more practically, reuse – electronic waste.
E-waste is often exported to developing countries
Electronic waste processing systems have matured in recent years following increased regulatory, public, and commercial scrutiny, and a commensurate increase in entrepreneurial interest. Part of this evolution has involved greater diversion of electronic waste from energy intensive, down-cycling processes (eg. conventional recycling) where equipment is reverted to a raw material form. This diversion is achieved through reuse and refurbishing. The environmental and social benefits of reuse are several: diminished demand for new products and their commensurate requirement for virgin raw materials (with their own environmental externalities not factored into the cost of the raw materials) and larger quantities of pure water and electricity for associated manufacturing, less packaging per unit, availability of technology to wider swaths of society due to greater affordability of products, and diminished use of landfills.
Challenges remain, when materials cannot or will not be reused, conventional recycling or disposal via landfill often follow. Standards for both approaches vary widely by jurisdiction, whether in developed or developing countries. The complexity of the various items to be disposed of, cost of environmentally sound recycling systems, and the need for concerned and concerted action to collect and systematically process equipment are the resources most lacked -- though this is changing. Many of the plastics used in electronic equipment contain flame retardants. These are generally halogens added to the plastic resin, making the plastics difficult to recycle.
Trends in disposal and recycling
WEEE Man
In the 1990s some European countries banned the disposal of electronic waste in landfills. This created an e-waste processing industry in Europe.
In Switzerland the first electronic waste recycling system was implemented in 1991 beginning with collection of old refrigerators. Over the years, all other electric and electronic devices were gradually added to the system. Legislation followed in 1998 and since January 2005 it has been possible to return all electronic waste to the sales points and other collection points free of charge. There are two established PROs (Producer Responsibility Organizations): SWICO mainly handling electronic waste and SENS mainly responsible for electrical appliances. The total amount of recycled electronic waste exceeds 10 kg per capita per year.[5][6][7]
The European Union has implemented a similar system under the Waste Electrical and Electronic Equipment Directive (WEEE 2002/96/EC). The WEEE Directive has now been transposed in national laws in all member countries of the European Union. The WEEE directive was designed to make equipment manufacturers financially or physically responsible for their equipment at its end-of-life under a policy known as extended producer responsibility (EPR). EPR was seen as a useful policy as it internalized the end-of-life costs and provided a competitive incentive for companies to design equipment with less costs and liabilities when it reached its end-of-life. However the application of the WEEE directive has been criticized for implementing the EPR concept in a collective manner and thereby losing the competitive incentive of individual manufacturers to be rewarded for their green design.[8] Since 13 August 2005, the electronics manufacturers became financially responsible for compliance to the WEEE directive. Under the directive, by the end of 2006 – and with one or two years' delay for the new EU members – every country has to recycle at least 4 kg of e-waste per capita per year.
Some states in recent years in the US developed policies banning CRTs from landfills due to the fear that the heavy metals contained in the glass would eventually leach into groundwater. Circuit boards also contain considerable quantities of lead-tin solders and are even more likely to leach into groundwater or become air pollution if managed in an incinerator. Indeed, a policy of "diversion from landfill" has been the driver for legislation in many states requiring higher and higher volumes of e-waste to be collected and processed separate from the solid waste stream. Today the e-waste recycling business is in all areas of the developed world a big and rapidly consolidating business. Unfortunately, increased regulation of e-waste and concern over the environmental harm which can result from toxic e-waste has raised disposal costs. This has had the unforeseen effect of providing brokers and others calling themselves recyclers with an incentive to export the e-waste to developing countries. This form of toxic trade was first exposed by the Basel Action Network (BAN) in their 2002 report and film entitled "Exporting Harm: The High-Tech Trashing of Asia".[9] Exporting Harm placed a spotlight on the global dumping of electronic waste, primarily from North America on a township area of China known as Guiyu. To this day in Guiyu, thousands of men, women and children are employed, in highly polluting, primitive recycling technologies, extracting the metals, toners, and plastics from computers and other e-waste. Because the United States has not ratified the Basel Convention or the Basel Ban Amendment, and has no domestic laws forbidding the export of toxic waste, BAN estimates that about 80% of the e-waste directed to recycling in the US does not get recycled there at all but is put on container ships and sent to countries such as China.[10][3] High Tech Trash: Digital Devices, Hidden Toxics, and Human Health by Elizabeth Grossman [Island Press, 2006, 2007.]
In developed countries, e-waste processing usually first involves dismantling the equipment into various parts — metal frames, power supplies, circuit boards, and plastics — which are separated, often by hand. Alternatively, material is shredded, and sophisticated expensive equipment separates the various metal and plastic fractions, which then are sold to various smelters and or plastics recyclers. From 2004 the state of California introduced a Electronic Waste Recycling Fee on all new monitors and televisions sold to cover the cost of recycling. The amount of the fee depends on the size of the monitor. That amount was adjusted on July 1, 2005 in order to match the real cost of recycling. Canada has also begun to take responsibility for electronics recycling. For example, in August of 2007 a fee similar to the one in California was added to the cost of purchasing new televisions, computers, and computer components in British Columbia. The new legislation made recycling mandatory for all of those products.
A typical electronic waste recycling plant as found in some industrialized countries combines the best of dismantling for component recovery with increased capacity to process large amounts of electronic waste in a cost effective-manner. Material is fed into a hopper, which travels up a conveyor and is dropped into the mechanical separator, which is followed by a number of screening and granulating machines. The entire recycling machinery is enclosed and employs a dust collection system. The European Union, South Korea, Japan and Taiwan have already demanded that sellers and manufacturers of electronics be responsible for recycling 75% of them.
Many Asian countries have legislated, or will do so, for electronic waste recycling.
The United States Congress is considering a number of electronic waste bills including the National Computer Recycling Act introduced by Congressman Mike Thompson (D-CA). This bill has continually stalled, however.
In the meantime, several states have passed their own laws regarding electronic waste management. California was the first state to enact such legislation, followed by Maryland, Maine, Washington and Minnesota. More recently, legislatures in Oregon and Texas passed their own laws.
List of substances contained in electronic waste
Substances in bulk
Polychlorinated biphenyls (PCBs), polyvinyl chloride (PVC), thermosetting plastics, epoxy resins, and fibre glass.
Elements in bulk
Lead, tin, copper, silicon, beryllium, carbon, iron and aluminium
Elements in small amounts
Cadmium, mercury, thallium[11]
Elements in trace amounts (alphabetical)
Americium, antimony, arsenic, barium, bismuth, boron, cobalt, europium, gallium, germanium, gold, indium, lithium, manganese, nickel, niobium, palladium, platinum, rhodium, ruthenium, selenium, silver, tantalum, terbium, thorium, titanium, vanadium, and yttrium.
List of example applications of the above elements and substances
Almost all electronics contain lead and tin (as solder) and copper (as wire and PCB tracks), though the use of lead-free solder is now spreading rapidly.
Lead: solder, CRT monitors (lead in glass), lead-acid batteries
Tin: solder, coatings on component leads
Copper: copper wire, printed circuit board tracks, component leads
Cadmium: light-sensitive resistors, corrosion-resistant alloys for marine and aviation environments
Aluminium: nearly all electronic goods using more than a few watts of power (heatsinks), electrolytic capacitors.
Beryllium oxide: filler in some thermal interface materials such as thermal grease used on heatsinks for CPUs and power transistors,[12] magnetrons, X-ray-transparent ceramic windows, heat transfer fins in vacuum tubes, and gas lasers.
Iron: steel chassis, cases and fixings
Silicon: glass, transistors, ICs, printed circuit boards.
Nickel and cadmium: nickel-cadmium batteries
Lithium: lithium-ion battery
Zinc: plating for steel parts
Gold: connector plating, primarily in computer equipment
Americium: smoke alarms (radioactive source)
Germanium: 1950s–1960s transistorised electronics (bipolar junction transistors)
Mercury: fluorescent tubes (numerous applications), tilt switches (pinball games, mechanical doorbells, thermostats)
Sulphur: lead-acid batteries
Carbon: steel, plastics, resistors. In almost all electronic equipment.
Polychlorinated biphenyls (PCBs) (prior to ban): in almost all 1930s–1970s equipment including capacitors, transformers, wiring insulation, paints, inks, and flexible sealants
See also
Electronics Portal
Waste Electrical and Electronic Equipment Directive
Electronic Waste Recycling Act
Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal
Digger gold
Electronic Waste Recycling Fee
Free Geek - recycling and re-using computer equipment based on the 'Free to all' philosophy.
Green computing
Polychlorinated biphenyls - see Handling Procedures
Solving the E-waste Problem or StEP
RoHS
Computer recycling
Silicon valley toxics coalition
References
^ Where does all the e-waste go? Greenpeace International
^ Slade, Giles. "iWaste", Mother Jones, 2007-04-01. Retrieved on 2007-04-03.
^ BAN and SVTC. 2002. "Exporting Harm: The High-Tech Trashing of Asia". Seattle and San Jose: Basel Action Network and Silicon Valley Toxics Coalition, February 25, 2002. Available: http://www.ban.org/E-waste/technotrashfinalcomp.pdf
^ Karlyn Black Kaley, Jim Carlisle, David Siegel, Julio Salinas (October 2006). Health Concerns and Environmental Issues with PVC-Containing Building Materials in Green Buildings (pdf), Integrated Waste Management Board, California Environmental Protection Agency, USA, p.11. Retrieved on 2007-08-03.
^ Umwelt Schweiz, Accessed 24.11.06
^ Swico, Accessed 24.11.06
^ SENS, Accessed 24.11.06
^ Lost In Transposition?, Greenpeace Report, 27 September 2006, [1]
^ "High-Tech Trash", National Geographic Magazine, January 2008. [2]
^ America Ships Electronic Waste Overseas By Terence Chea, Associated Press, 11/18/07.
^ Chemical fact sheet — Thallium. Spectrum Laboratories. Retrieved on 2008-02-02.
^ Greg Becker, Chris Lee, and Zuchen Lin (Jul 2005). "Thermal conductivity in advanced chips — Emerging generation of thermal greases offers advantages". Advanced Packaging: pp.2-4. Retrieved on 2008-03-04.
^High Tech Trash: Digital Devices, Hidden Toxics, and Human Health by Elizabeth Grossman (Island Press, 2006, 2007) ^Where Computers Go to Die....And Kill by Elizabeth Grossman, Salon, April 2006
External links
The external links in this article may not follow Wikipedia's content policies or guidelines.Please improve this article by removing excessive or inappropriate external links.
The Secret Life of Cell Phonesan INFORM, Inc. Video Project
e-Waste Guide A knowledge base for the sustainable recycling of e-Waste
Indian e-Waste Guide A knowledge base for the sustainable recycling of e-Waste specific to India
European Commission WEEE page
RoHS directive (PDF)
WEEE directive (PDF)
US EPA's 'eCycling' Program
Inside the Digital Dump, a photoessay from Foreign Policy Magazine
BBC Article "Gadget recycling foxes consumers"
The Electronic Waste Problem
Greenpeace Electronic Waste Campaign
Greener Computing - covers eWaste and other green computing issues
Recent 'bust' illuminates underground electronics export business in Canada Canada.com accessed December 22, 2006
WEEE was not thought through
The e-waste problem in China
[hide]
v • d • e
Topics related to waste management
Anaerobic digestion · Composting · Eco-industrial park · Incineration · Landfill · Mechanical biological treatment · Radioactive waste · Reuse · Recycling · Regiving · Sewerage · Waste · Waste collection · Waste sorting · Waste hierarchy · Waste management concepts · Waste legislation · Waste treatment
Subscribe to:
Posts (Atom)
