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transistor
bipolar transistor
bipolar transistor A semiconductor device having three electrodes:
emitter,
base, and
collector. It is effectively a sandwich of two types of doped
semiconductor, usually p-type and n-type silicon, and so contains two p-n
junctions. When the region common to both junctions is p-type, an
npn transistor is formed; when it is n-type a
pnp transistor is formed. This central region forms the base electrode.
Bipolar transistors are so named because both charge carriers, i.e. electrons and holes, contribute to the flow of current. Current flow between collector and emitter is established by applying a
forward bias between base and emitter. In linear (i.e.
nonsaturated) operation, the magnitude of this current is proportional to the input current drawn at the base. The current flow is in opposite directions in npn and pnp transistors.
If the base current is increased but the collector current is restrained, so that the transistor effectively receives more base current than it would seem to require, the transistor is driven into a state of
saturation, also known as
bottoming. It then behaves as a very efficient switch since the base-collector junction becomes
reverse-biased and, in saturation, the collector-emitter voltage can fall as low as 20 millivolts. The device thus seems virtually a short circuit. Bipolar transistor switches, working into saturation, are the basis of
TTL circuits. Saturated transistors do however have a fairly low switching speed. The much higher switching speeds of
Schottky TTL and
ECL circuits are achieved by using a nonsaturated mode of operation.
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 "The Economist (US)")
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Transistors: A tall story.(development of transistors that have a vertical current flow, rather than a horizontal one)(Brief Article)
Magazine article from: The Economist (US); 12/4/1999; 700+ words
; ...and the fact that the gate length does not vary from transistor to transistor, should help chips that are built using vertical transistors to run faster. Furthermore, each transistor has two gates--one on either side of the channel...
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Transistor development tunnels full speed ahead
Newspaper article from: The Journal Record; 3/24/1998; 700+ words
; ...The Sandia transistors are about the...traditional transistor -- a square...common silicon transistor, a gate opens...the Sandia transistors, electrons...traditional transistors. The Sandia transistor is expected...
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Transistors of the future: will diamonds be an engineer's best friend?
Magazine article from: EDN; 7/17/1997; ; 700+ words
; ...existing processes. The speed of a transistor relates to its size, which affects...have to travel. Thus, to enable transistors to switch faster, technologists...transistors. However, as you reduce the transistor structures, you must maintain...
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Transistor laser a non-linear switch, processor.(Editorial)
Magazine article from: Semiconductor International; 3/1/2006; ; 700+ words
; ...colleagues have shifted the transistor operation from spontaneous...recombination process of the transistor changes the device characteristics...Applied Physics Letters. "Transistors have never done this before...Operating as a new form of transistor, the transistor laser offers...
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Transistor Tester.(building a tester)(Brief Article)
Magazine article from: Poptronics; 2/1/2002; ; 700+ words
; ...bipolar junction transistors to determine what type of transistor I have and...bi-polar transistors is shown in...determine transistor type (NPN...your unknown transistors. First...leads of the transistor into the socket...
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Intel's Transistor Technology Breakthrough Represents Biggest Change to Computer Chips in 40 Years.
Business Wire; 1/27/2007; 700+ words
; ...Tiny 45 Nanometer Transistors, Accelerating...in fundamental transistor design, Intel...biggest change in transistor technology since...polysilicon gate MOS transistors in the late 1960s...costs and cost per transistor. To maintain this...of innovation, transistors must continue to...
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Transistor Design Advances Drive SOI into the Mainstream.(silicon-on-insulator technology)
Magazine article from: R & D; 7/1/1999; ; 700+ words
; ...miniaturization, of the transistor. As a transistor becomes smaller...power. As long as transistors can continue being...semiconductor (MOS) transistor works, and to do...understand how MOS transistors are built. Recall...
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Transistor technologies for RFICs in wireless applications. (radio frequency integrated circuits)
Magazine article from: Microwave Journal; 2/1/1998; ; 700+ words
; ...electron mobility transistor (HEMT) technologies...technologies, such as transistors based on InP and...HBT is a bipolar transistor that uses bandgap...bipolar junction transistors (BJT) for several...approach for both transistors is identical...shows the minimum transistor feature ...
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TRANSISTOR LASER FUNCTIONS AS NON-LINER ELECTRONIC SWITCH, PROCESSOR
News Wire article from: US Fed News Service, Including US State News; 2/6/2006; 700+ words
; ...colleagues have shifted the transistor operation from spontaneous...recombination process of the transistor changes the device characteristics...Applied Physics Letters. "Transistors have never done this before...Operating as a new form of transistor, the transistor laser offers...
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Revolutionary Transistor Design From Lucent's Bell Labs May Turn Silicon World On End.
Business Wire; 11/15/1999; 700+ words
; ...horizontally and the transistors are formed within the...that a conventional transistor has only one "gate...nanometers. The vertical transistor design also may help...when making smaller transistors: the ever shrinking...layer lies between the transistor's gate and the channel...
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transistor
Book article from: The Columbia Encyclopedia, Sixth Edition
transistor three-terminal, solid-state...to the triode electron tube ; the transistor has replaced the electron tube for...all common applications. Types of Transistors The transistor is an arrangement of semiconductor...
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Transistors
Book article from: Computer Sciences
...They were called "transistor radios," or simply "transistors," and were extremely...and much faster. Transistor Basics Transistors are made from crystals...as in a silicon transistor. How Are Transistors Made? Although a...
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The Transistor
Book article from: American Decades
THE TRANSISTOR Vacuum Tubes Before transistors, electronic...the original transistor. One was obtaining...quantities of transistors. The other...come and learn transistor technology...products using transistors. One of these...
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bipolar transistor
Book article from: A Dictionary of Computing
...n-type a pnp transistor is formed. This...electrode. Bipolar transistors are so named because...in npn and pnp transistors. If the base current...restrained, so that the transistor effectively receives...circuit. Bipolar transistor switches, working...circuits. Saturated transistors ...
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transistor-transistor logic
Book article from: A Dictionary of Computing
transistor-transistor logic See TTL .
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