Bipolar junction transistor, Electrical Engineering

Bipolar junction transistor:

Transistors are so named as they conduct via using both majority and minority carriers. The bipolar junction transistor that is abbreviated as BJT, the first type of transistor to be mass-produced, is a mixture of two junction diodes, and is made up of either a thin layer of p-type semiconductor sandwiched among the two n-type semiconductors (an n-p-n transistor), or a thin layer of n-type semiconductor sandwiched among the two p-type semiconductors (a p-n-p transistor). This construction generates two p-n junctions: a base-emitter junction and a base-collector junction, separated via a thin region of semiconductor termed as the base region (two junction diodes wired together with no sharing an intervening semiconducting region will not make a transistor).

The BJT or bipolar junction transistor has three terminals that are corresponding to the three layers of semiconductor - an emitter, base, and collector. It is helpful in amplifiers as the currents at the emitter and collector are controllable through a comparatively small base current." In the active region, the emitter-base junction is forward biased and electrons are injected into the base region, in an NPN transistor operating. Since the base is narrow, most of these electrons will diffuse into the reverse-biased (electrons and holes are made at, and move away from the junction) base-collector junction and be swept into the collector; may be one-hundredth of the electrons will recombine in the base that is the dominant mechanism in the base current. Through controlling the number of electrons which can leave the base, the number (digit) of electrons entering the collector can be controlled. Collector current is almost β (common-emitter current gain) times the base current. It is commonly greater than 100 for small-signal transistors but can be much smaller in transistors intended for high-power applications.

Posted Date: 1/10/2013 6:31:30 AM | Location : United States







Related Discussions:- Bipolar junction transistor, Assignment Help, Ask Question on Bipolar junction transistor, Get Answer, Expert's Help, Bipolar junction transistor Discussions

Write discussion on Bipolar junction transistor
Your posts are moderated
Related Questions
Explain Information Obtained for the Load Flow Analysis (i)  Magnitude and phase angle of the voltage at each bus. (ii)  Active and Reactive power flow in each line. (iii

a shunt motor supplied at 230V rms runs at 900rev/min when the armature current is 30A.the resistance of the armature circuit is 0.4 ohms.find the armature input

Write short notes of the following. a)    Microprocessor b)    Modes of data transfer. c)    I/O processor d)    Associative memory e)    Software and Hardware interrupt

Q. Show the Storage Layout of digital system? The IEEE floating point numbers have three basic components: the sign, the exponent, and the mantissa. A mantissa is composed of t

Consider an electromagnet, as shown in Figure, which is used to support a solid piece of steel and is excited by a coil of N = 1000 turns carrying a current i = 1.5 A. The cross-se

Q. Explain different Routing plan adopted in a Telephone network.  Ans: Hierarchical networks are capable of handling heavy traffic where required, and at the same time us

In this project we will consider the control of a synchronous generator supplying electricity to the grid. We will focus on the problem of frequency stability. The frequency at whi



how is working transfmer?