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Topic: Field effect transistor


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FET

In the News (Wed 2 Dec 09)

  
 Field Effect Transistors
The common transistor is called a junction transistor, and it was the key device which led to the solid state electronics revolution.
In application, the junction transistor has the disadvantage of a low input impedance because the base of the transistor is the signal input and the base-emitter diode is forward biased.
For an n-channel FET, the device is constructed from a bar of n-type material, with the shaded areas composed of a p-type material as a Gate.
hyperphysics.phy-astr.gsu.edu /hbase/electronic/fet.html   (555 words)

  
 iqexpand.com   (Site not responding. Last check: 2007-11-07)
Transistor was also the common name in the sixties for a transistor radio, a pocket-sized portable radio that used transistors (rather than vacuum tubes) as its active electronic components.
The transistor, considered by many to be one of the greatest inventions in modern history, ranks with the printing press and banking.
In bipolar transistors, the semiconductor is formed into structures called p-n junctions that allow electricity to flow in only one direction through them – that is, they are a conductor when voltage is applied in one direction, and an insulator when it is applied in the other direction.
transistors.iqexpand.com   (5180 words)

  
 Thin-film transistor - Wikipedia, the free encyclopedia
A thin film transistor (TFT) is a special kind of field effect transistor made by depositing thin films for the metallic contacts, semiconductor active layer, and dielectric layer.
The best known application of thin-film transistors is in TFT LCDs, a variant of LCD technology.
Transistors are embedded within the panel itself, reducing crosstalk between pixels and improving image stability.
en.wikipedia.org /wiki/Thin-film_transistor   (184 words)

  
 Field-Effect Transistor   (Site not responding. Last check: 2007-11-07)
The gate on the FET passes virtually no current when driven with D.C. When driving the gate with high frequency pulsed D.C. or A.C. there may be a small amount of current flow.
When the FET starts to turn on, the voltage on the drain starts to fall (indicated by the falling green line and the point where the green curve intersects with the white line).
FETs are similar to bipolar transistors as far as packages and power dissipation go, and you can follow this link back to the bipolar page for more information.
www.bcae1.com /tranfet.htm   (1476 words)

  
 Junction FET Tutorial
The J-FET (Junction Field Effect Transistor) and the MOS-FET (Metal-Oxide-Semiconductor FET) are voltage controlled devices: that is a small change in input voltage causes a large change in output current.
FET operation involves an electric field which controls the flow of a charge (current) through the device.
The source, drain, and gate terminal of the FET are analagous to the emitter, collector, and base of a bipolar transistor.
www.americanmicrosemi.com /tutorials/junctionfet.htm   (347 words)

  
 FETs
The FET operates by the effects of an electric field on the flow of electrons through a single type of semiconductor material.
The polarity of the electric field that controls current in the channel is determined by the majority carriers of the channel, ordinarily positive for P-channel FETs and negative for N-channel FETS.
In the junction FET (JFET), the gate material is made of the opposite polarity semiconductor to the channel material (for a P-channel FET the gate is made of N-type semiconductor material).
www.williamson-labs.com /480_fet.htm   (1089 words)

  
 Silicon carbide field-effect transistor with improved breakdown voltage and low leakage current - Patent 5170231   (Site not responding. Last check: 2007-11-07)
A silicon carbide field-effect transistor according to claim 1, wherein the channel formation layer is formed on the drain region, and the source region is formed on the channel formation layer.
A silicon carbide field-effect transistor according to claim 1, wherein the first contact is a p-n junction having excellent electric characteristics in the reverse direction thereof and the second contact is a p-n junction having excellent electric characteristics in the forward direction thereof.
A silicon carbide field-effect transistor according to claim 1, wherein the first contact is a p-n junction having excellent electric characteristics in the reverse direction thereof and the second contact is a Schottky junction having excellent electric characteristics in the forward direction thereof.
www.freepatentsonline.com /5170231.html   (4862 words)

  
 Field effect transistor at opensource encyclopedia   (Site not responding. Last check: 2007-11-07)
The Field-Effect Transistor (FET) is a type of transistor that works by modulating an electric field inside a semiconductor material.
Most FETs are made using conventional bulk semiconductor processing techniques, which use a single crystal of silicon as the starting material.
The effect of this junction is to create a very thin layer where the Fermi energy is above the conduction band, giving the channel very low resistance (or to put it another way, "high electron mobility").
www.wiki.tatet.com /Field_effect_transistor.html   (1309 words)

  
 Silicon carbide MOS type field-effect transistor with at least one of the source and drain regions is formed by the use ...   (Site not responding. Last check: 2007-11-07)
The field-effect transistor has source and drain regions formed in the silicon carbide layer, between which the MOS structure is disposed, wherein at least one of the source and drain regions is formed by the use of a Schottky contact on the silicon carbide layer.
A silicon carbide field-effect transistor according to claim 1, wherein said Schottky contact is formed on the p-type silicon carbide with a metal which is selected from the group consisting of aluminum (Al) and silver (Ag).
This invention relates to a silicon carbide field-effect transistor and more particularly to a silicon carbide field-effect transistor having source and drain regions in a silicon carbide layer, at least one of the source and drain regions being formed by the use of a Schottky contact on the silicon carbide layer.
www.freepatentsonline.com /5216264.html   (2231 words)

  
 Transistor houses two independent gates - ZDNet UK News
A transistor is a microscopic on-off switch inside a chip that -- depending on whether a gate is allowing electricity to pass through it -- is read as a one or a zero by the computer.
Most multiple-gate transistors are being proposed as a way to offload the drive current, which is the amount of electricity required to operate a semiconductor, onto a greater number of circuits.
Motorola did not commit to when such transistors could be included in their processors, but different manufacturers have said that enhancements like this could emerge with the 45-nanometre manufacturing process, which is expected to debut in 2007 or 2008.
news.zdnet.co.uk /hardware/chips/0,39020354,39117784,00.htm   (506 words)

  
 Field Effect (Modern) Transistors
Field-effect transistors are so named because a weak electrical signal coming in through one electrode creates an electrical field through the rest of the transistor.
This field flips from positive to negative when the incoming signal does, and controls a second current traveling through the rest of the transistor.
The transistor is used this way for stereo amplification in speakers and microphones, as well as to boost telephone signals as they travel around the world.
www.pbs.org /transistor/science/info/transmodern.html   (886 words)

  
 field-effect transistor - a Whatis.com definition - see also: FET   (Site not responding. Last check: 2007-11-07)
A field-effect transistor (FET) is a type of transistor commonly used for weak-signal amplification (for example, for amplifying wireless signals).� The device can amplify analog or digital signals.� It can also switch DC or function as an oscillator.
The junction FET has a channel consisting of N-type semiconductor (N-channel) or P-type semiconductor (P-channel) material; the gate is made of the opposite semiconductor type.� In P-type material, electric charges are carried mainly in the form of electron deficiencies called holes.
The FET has some advantages and some disadvantages relative to the bipolar transistor.� Field-effect transistors are preferred for weak-signal work, for example in wireless communications and broadcast receivers.
whatis.techtarget.com /definition/0,,sid9_gci213961,00.html   (330 words)

  
 FET
Transistors are the basic building blocks of integrated circuits.
We have successfully fabricated and tested nanotube transistors using individual multi-wall or single-wall nanotubes as the channel of a field-effect transistor (FET).
As we cool the FET down from room temperature to 4 degree Kelvin (minus 460 degree Fahrenheit) we see the device behavior change dramatically.
www.research.ibm.com /nanoscience/fet.html   (174 words)

  
 ...trailing the Transistor : Types : JFET : Scientific Aspects   (Site not responding. Last check: 2007-11-07)
In a working transistor, the current that is to be amplified is flows through the channel (shown in fl).
If the electric field is decreased, the current in the channel increases and if the electric field is increased, the current decreases.
To understand the impact of the transistor in its entirety, perceive what the world was before, and what it is after 1947 - when the transistor was invented.
library.thinkquest.org /C006224/jfet.html??   (1121 words)

  
 transistors
There is a further type known as a FET transistor which is an inherently high input impedance transistor with behaviour somewhat comparable to valves.
Transistors, I was once told, "were the fastest acting fuse known to mankind".
In fact the amplitude (magnitude) of the collector current in a transistor is determined mainly by the emitter current which in turn is determined by current flowing into the base of the transistor.
www.electronics-tutorials.com /basics/transistors.htm   (2001 words)

  
 Duke Chemists Describe New Kind Of Nanotube Transistor
Field effect transistors, among the workhorse devices of microelectronics technology, are tiny switches in which the passage of electric current between a "source" and a "drain" is controlled by an electric field in a middle component called a "gate."
The Duke research group headed by Liu is among a number that have incorporated a semiconducting nanotube as a component in an experimental field effect transistor.
The nanotube is grown on a surface of silicon dioxide with metal electrodes evaporated on the nanotube's surface serving as the device's electron source and drain.
www.spacedaily.com /news/nanotech-04q.html   (822 words)

  
 Field Effect Transistors
The "source" and "drain" elements of the JFET correspond to the emitter and collector of the transistor and to the cathode and plate of the vacuum tube.
The key to FET operation is the effective cross-sectional area of the channel, which can be controlled by variations in the voltage applied to the gate.
Because this region has a reduced number of current carriers, the effect of reverse biasing is to reduce the effective cross-sectional area of the "channel." This reduction in area increases the source-to-drain resistance of the device and decreases current flow.
www.tpub.com /neets/book7/26i.htm   (971 words)

  
 Types Of Bipolar Junction Transistors   (Site not responding. Last check: 2007-11-07)
There are two general types of transistors in use today: (1) the bipolar transistor (often called the bipolar junction transistor, or BJT), and (2) the field-effect transistor (FET).
See.....A bipolar junction transistor (BJT) is a type of transistor, an amplifying or switching...
Transistors are of two main types: bipolar junction transistors (BJT's) and field effect transistors (FET's).
www.healinghopes.org /types-of-bipolar-junction-transistors.html   (244 words)

  
 Semiconductors basics   (Site not responding. Last check: 2007-11-07)
A subgroup of TFTs are organic field effect transistors that are based on organic semiconductors and often apply organic gate insulators and electrodes.
The channel region of any FET is either doped to produce n-type semiconductor, giving an "N-channel" device, or with p-type to give a "P-channel" device.
The shape of the conducting channel in an FET is altered when a potential is applied to the Gate terminal (potential relative to either Source or Drain.) In an N-channel device, a negative Gate potential causes an insulating Depletion Zone to expand in size and encroach on the channel from the side, narrowing the channel.
www.semiconductorsinfo.net /fet.html   (1151 words)

  
 IBM Zurich Research Laboratory, News
Size and performance of individual transistors on microelectronic chips depend to a large extent on a thin layer between the transistor gate and the semiconducting silicon.
The dielectric properties desired in transistors depend on the geometry of the structure, i.e.
The general consensus is that this approach allows continuation of transistor downscaling, from today's minimum lateral dimensions of 130 nm to the range of 50 -100 nanometers.
www.zurich.ibm.com /news/01/invest.html   (733 words)

  
 Ions Feel the Field Effect
The central "gate" electrode (gold) in a fluid-based transistor controls the flow of either positively- or negatively-charged ions through the water inside a silicon nanotube.
As in ordinary field-effect transistors, the voltage on a "gate" electrode controls the rate of ion flow through the water-filled tube.
The anion-conducting tubes are analogous to n-type transistors, he says, so the group can now begin assembling more complicated systems such as diodes--perhaps made of two nanotubes--and, in principle, integrated circuits for building miniature biochemical analysis devices.
focus.aps.org /story/v16/st6   (711 words)

  
 Gallium indium nitride arsenide based epitaxial wafer, a hetero field effect transistor using the wafer, and a method ...
Gallium indium nitride arsenide based epitaxial wafer, a hetero field effect transistor using the wafer, and a method of fabricating the hetero field effect transistor
Gallium indium nitride arsenide based epitaxial wafer, a hetero field effect transistor using the wafer.
And a method of fabricating the hetero field effect transistor field effect transistor, layer formed adjacent, effect transistor.
www.patentalert.com /docs/001/z00164987.shtml   (128 words)

  
 Learn Electronics Lessons and Information Pages
(MOSFET) A field effect transistor in which the insulating layer betwen the gate electrode and the channel is a metal oxide layer.
Abbreviation for "metal oxide field effect transistor" also known as an "insulated gate field effect transistor).
A field effect transistor in which the insulating layer betwen the gate electrode and the channel is a metal oxide layer.
www.twysted-pair.com /dictm.htm   (810 words)

  
 Transistor Circuits   (Site not responding. Last check: 2007-11-07)
Transistors are active circuit elements and are typically made from silicon or germanium and come in two types.
The bipolar transistor controls the current by varying the number of charge carriers.
The field effect transistor (FET) varies the current by varying the shape of the conducting volume.
www.phys.ualberta.ca /~gingrich/phys395/notes/node74.html   (148 words)

  
 Richer, Ira (1964-05-21) Properties of an arbitrarily doped field-effect transistor. ...
The properties of p-n junction field-effect transistors (FET's) are formulated on a general basis, in terms of an arbitrary doping profile (i.e.
More specifically, upper and lower bounds are obtained on the normalized transconductance, drain current, input capacitance, and bias point for zero temperature coefficient of the drain current, and on the voltage-dependent parts of various figures of merit.
Finally, a complete, small-signal, low-frequency equivalent circuit for an arbitrarily doped FET is developed by considering the capacitive current that flows between the channel and the gate.
etd.caltech.edu /etd/available/etd-09272002-160258   (252 words)

  
 Field Effect Transistor   (Site not responding. Last check: 2007-11-07)
In switching applications, field effect transistors are preferred because they consume less power.
FET's also have a NPN (or PNP) sequence of materials.
By adjusting the voltage between the gate and the substrate, the width of a conducting channel between source and drain can be controlled.
thalia.spec.gmu.edu /%7Epparis/classes/notes_101/node102.html   (99 words)

  
 Learn Electronics Lessons and Information Pages
(FET) A voltage controlled transistor in which the source to drain conduction is controlled by gate to source voltage.
In magnetism, the magnetic field consisting of lines of force.
Sustaining effect of oscillation in an LC circuit.
www.twysted-pair.com /dictf.htm   (522 words)

  
 ScienceDaily: Detecting The Spin Of A Single Electron
The spin orientation of the electron was converted to an electrical charge, which was then measured using a device called a Field effect transistor, or FET.
According to Martin, who developed the theory for the effect together with Los Alamos postdoctoral researcher Dima Mozyrsky, "We believe this is a significant advance in the field of quantum physics.
The more that the fields of science and engineering learn about the enigmatic physics of electron spin, the more we will be able to use that knowledge in the future to create nanoscale technologies like spin electronic and quantum computers, that are based on electron spin control."
www.sciencedaily.com /releases/2004/08/040811080351.htm   (875 words)

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