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Topic: Transistor


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In the News (Sat 22 Sep 18)

  
  transistor. The Columbia Encyclopedia, Sixth Edition. 2001-05
The transistor action is such that if the electric potentials on the segments are properly determined, a small current between the base and emitter connections results in a large current between the emitter and collector connections, thus producing current amplification.
The metal-oxide semiconductor field-effect transistor (MOSFET) is a variant in which a single gate is separated from the channel by a layer of metal oxide, which acts as an insulator, or dielectric.
Although discrete transistors are still used significantly, the vast majority of transistors are built as parts of integrated circuits.
www.bartleby.com /65/tr/transist.html   (586 words)

  
 Transistor
The transistor was invented at Bell Laboratories in December...
A transistor is a small electronic device that can cause changes in a large electrical output signal by small changes in a small input signal.
Transistors are either NPN or PNP in the configuration of the layers.
www.101science.com /transistor.htm   (599 words)

  
 Transistor Circuits
When a transistor is saturated the collector current Ic is determined by the supply voltage and the external resistance in the collector circuit, not by the transistor's current gain.
A transistor can also be used to enable a chip connected to a low voltage supply (such as 5V) to switch the current for an output device with a separate higher voltage supply (such as 12V).
If the transistor is switching a load with a coil, such as a motor or relay, remember to add a protection diode across the load.
www.kpsec.freeuk.com /trancirc.htm   (2210 words)

  
 Quantum mechanical transistor
The quantum mechanical transistor is the equivalent of turning on a light bulb without closing a switch: Electrons "tunnel" from path to path through a barrier that, according to classical physics, is impenetrable.
Actual use of the transistor by industry may be years in the future because of other engineering problems to be tackled.
Schematic of the structure of the DELTT transistor.
www.sandia.gov /media/quantran.htm   (1153 words)

  
 Mister Transistor's Historic Semiconductors
The transistor was invented at Bell Laboratories in December 1947 (not in 1948 as is often stated) by John Bardeen and Walter Brattain.
In September 1951 Bell held a transistor symposium, and licensed their technology for both types of transistor to anyone who paid the required fee of 25 thousand dollars.
This was the start of the transistor industry which has changed the way that we live, in the Western world at least.
ourworld.compuserve.com /homepages/Andrew_Wylie/history.htm   (429 words)

  
  The Transistor - History
For many years, transistors were made as individual electronic components and were connected to other electronic components (resistors, capacitors, inductors, diodes, etc.) on boards to make an electronic circuit.
The transistor circuits were faster than vacuum tube circuits, and there were noticeable problems due to time delays for electric signals to propagate a long distance in these large circuits.
From the dawn of the vacuum tube triode, to the discovery of the transistor and the development of the integrated circuit, the 20th century has certainly been the century of electronics.
nobelprize.org /educational_games/physics/transistor/history/index.html   (1290 words)

  
  Transistor - Wikipedia, the free encyclopedia
Transistors are made either as separate components or as part of an integrated circuit.
The transistor is considered by many to be one of the greatest inventions in modern history, ranking in importance with the printing press, automobile and telephone.
Transistorized circuits are replacing electromechanical devices for the control of appliances and machinery as well.
en.wikipedia.org /wiki/Transistor   (3394 words)

  
 Transistor   (Site not responding. Last check: )
A bipolar transistor has base, emitter and collector electrodes, and is a current-controlled device (able to deliver a change in output voltage in response to a change in input current) with a low input impedance.
Point-contact transistors, though, were essentially laboratory curiousities -- they were hard to make (performance depended on the exact placement of the wires on the germanium), and none too reliable (since they responded nearly as much to their surroundings as to their input signals).
In the bipolar transistor (as in all modern transistors), the vital junctions between the N-type and P-type layers are buried deep within the semiconductor crystal where they cannot be affected by their surroundings.
encyclobeamia.solarbotics.net /articles/transistor.html   (684 words)

  
 Transistor
The transistor is an arrangement of semiconductor materials that share common physical boundaries.
The transistor action is such that if the electric potentials on the segments are properly determined, a small current between the base and emitter connections results in a large current between the emitter and collector connections, thus producing current amplification.
The p-n-p junction transistor, consisting of a thin layer of n-type semiconductor lying between two p-type semiconductors, works in the same manner, except that all polarities are reversed.
www.mtmi.vu.lt /pfk/funkc_dariniai/transistor   (1073 words)

  
 Transistor radio - Wikipedia, the free encyclopedia
RCA had demonstrated a prototype transistor radio as early as 1952 and it is likely that they and the other radio makers were planning transistor radios of their own.
The use of transistors instead of vacuum tubes as the amplifier elements meant that the device was much smaller and required far less power to operate than a tubed radio.
By comparison, the "transistor" could fit in a pocket and weighed half a pound or less and was powered by standard flashlight batteries or a single compact 9 V battery.
en.wikipedia.org /wiki/Transistor_radio   (933 words)

  
 Define transistor - a definition from Whatis.com
The transistor, invented by three scientists at the Bell Laboratories in 1947, rapidly replaced the vacuum tube as an electronic signal regulator.
A transistor regulates current or voltage flow and acts as a switch or gate for electronic signals.
Transistors are the basic elements in integrated circuits (ICs), which consist of very large numbers of transistors interconnected with circuitry and baked into a single silicon microchip or "chip."
whatis.techtarget.com /definition/0,,sid9_gci213216,00.html   (344 words)

  
 IEEE Spectrum: The Transistor Laser   (Site not responding. Last check: )
On a hunch two years ago, we inspected in greater depth some samples of this transistor, which are made from indium phosphide and indium-gallium-arsenide, the same sort of semiconductor compounds used in today's light-emitting diodes and laser diodes.
We detected significant light in the base of these transistors and immediately began to engineer a new, more powerful kind of device, a transistor laser.
Our transistor puts out both electrical signals and a laser beam, which can be directly modulated to send optical signals at the rate of 10 billion bits per second.
www.spectrum.ieee.org /feb06/2800   (363 words)

  
 IBM Research | Press Resources | Chip Evolution: IBM Scientists Develop Breakthrough Transistor Technology with Carbon ...
Moore's Law states that the number of transistors that can be packed on a chip doubles every 18 months, but many scientists expect that within 10-20 years silicon will reach its physical limits, halting the ability to pack more transistors on a chip.
Transistors are a key building block of electronic systems -- they act as bridges that carry data from one place to another inside computer chips.
The more transistors on a chip, the faster the processing speed, indicating why this advance by IBM scientists could have a profound impact on the future of chip performance.
domino.research.ibm.com /comm/pr.nsf/pages/news.20010425_Carbon_Nanotubes.html   (898 words)

  
 Lessons In Electric Circuits -- Volume III (Semiconductors) - Chapter 4
Since a transistor tends to act as a current regulator, limiting collector current to a proportion set by the base current, it is useful to express this proportion as a standard transistor performance measure.
Because the transistor is a current-regulating device, and because meter movement indications are based on the amount of current through their movement coils, meter indication in this circuit should depend only on the amount of current from the solar cell, not on the amount of voltage provided by the battery.
Complementary pairs of transistors running in class B operation are often used to deliver high power amplification in audio signal systems, each transistor of the pair handling a separate half of the waveform cycle.
www.ibiblio.org /kuphaldt/electricCircuits/Semi/SEMI_4.html   (14585 words)

  
 BBC - Radio 4 You and Yours - Triumph of Technology: Transistor
Though the modern transistor performs many functions, it is its ability to amplify an electrical signal and to act as a switch for which it is celebrated.
Before the invention of the transistor in 1947, the flow of current in an electronic device could be controlled through the use of a vacuum tube.
Early transistors were just a few centimetres high, but today millions of silicon-based transistors can be fitted onto a computer chip.
www.bbc.co.uk /radio4/youandyours/technology_transistor.shtml   (202 words)

  
 Transistor
The two transistors on the left are among the earliest commercially available RCA transistors and date from 1953 and 1954.
Sylvania transistors initially became available in early 1955 and the 2N94 was among the first transistors to operate reliably at radio frequencies.
From l to r: a rare CK740 diode (constructed in a half-size CK series transistor case) from 1954, a 782 hearing aid transistor from 1956, a 2N138 from 1957, a CK768 from 1956 and finally a CK721 from 1953 (shown in a sub miniature hearing aid tube socket).
users.arczip.com /rmcgarra2/xstr.html   (6155 words)

  
 transistor
Notice that the transistor comes in a case, you must figure out which lead is which.
If the transistor is a 2N2222 the emitter, E, is the lead closest to the tab on the metal can, the base, B, is the second closest lead to the tab.
The transistor can be used as a switch where small electric currents traveling over long wires can control large currents at a distance, It can also be used as an amplifier where small currents control large currents.
www.exo.net /~pauld/activities/electronic/transistor.htm   (517 words)

  
 Transistors
An equivalent circuit of a NPN transistor is two diodes tied anode to anode; one cathode being the emitter, the other the collector, and the junction of the anodes is the base.
In the case of simple single transistor gain stages, the control exerted by the gain setting resistors is limited and has less effect on the stage's overall performance, i.e., the transistor's inherent gain is dominant.
Previously I said that the two input transistors share the same emitter resistor, leaving the impression that a signal voltage was at the junction of the emitters and Re.
www.williamson-labs.com /480_xtor.htm   (4332 words)

  
 IBM to reveal supertiny transistor | CNET News.com
Transistors are the tiny devices that make up a chip's circuitry, acting like an on-and-off switch for electrical signals; the gate is what turns it on and off.
IBM's new transistor, which is 10 times smaller than today's state-of-the-art transistors, proves that working transistors can continue to be made using current chip technology, or similar techniques, for 10 years or more into the future, IBM researchers said.
But one important feature of the new transistor is that it can be combined with "strained silicon," a manufacturing technique that promises to boost processor performance by up to 20 percent.
news.com.com /2100-1001-976423.html   (833 words)

  
 The MOS transistor
These transistors are formed as a ``sandwich'' consisting of a semiconductor layer, usually a slice, or wafer, from a single crystal of silicon; a layer of silicon dioxide (the oxide) and a layer of metal.
As a permanently ``on'' transistor, the device has a high resistance compared with the doped semiconductor material itself, and the resistance is readily variable by modifying the size of the transistor.
The depletion mode transistor is used as a ``pull-up'' resistor, and the enhancement mode transistor is used as a switch to ``pull down'' the output when the switch is turned on.
www.cs.mun.ca /~paul/transistors/node1.html   (1539 words)

  
 Howstuffworks "How Semiconductors Work"
A transistor is created by using three layers rather than the two layers used in a diode.
The natural progression from silicon to doped silicon to transistors to chips is what has made microprocessors and other electronic devices so inexpensive and ubiquitous in today's society.
The miracle is the constant refinement of those principles to the point where, today, tens of millions of transistors can be inexpensively formed onto a single chip.
electronics.howstuffworks.com /diode4.htm   (197 words)

  
 Sarah's Transistor Radios
Encore 10 Transistor Encore 78 Encore 615 Encore 6 Transistor Encore 8 Transistor Encore TFN-1003 Encore TR-1500 Encore 1288
Transitone TR-1645 Transix 6 Transistor Transonic 10 Transistor Transonic 7 Transistor
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www.transistor.org /collection/collection.html   (1711 words)

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