Storage delay and transistor alpha- beta, Electrical Engineering

Assignment Help:

Turn-on, turn-off, and storage delay:

The Bipolar transistor shows a few delay characteristics while turning on and off. Most of the transistors, and particularly power transistors, show long base storage time that limits maximum frequency of operation in switching applications. One technique for reducing this storage time is using a Baker clamp.

Transistor 'alpha' and 'beta':

The proportion of electrons capable to cross the base and reach the collector is a measure of the BJT (bipolar junction transistor) efficiency. The heavy doping of the emitter region and light doping of the base region origin several electrons to be injected from the emitter into the base than as compared to the holes to be injected from the base into the emitter. The common-emitter current gain is presented by βF or hfe; it is approximately the ratio of the DC collector current to the DC (direct current) base current in forward-active region. It is generally greater than 100 for small-signal transistors but can be smaller in transistors intended for high-power applications. An additional significant parameter is the common-base current gain, αF. The common-base current gain is almost the gain of current from emitter to collector in the forward-active region. This ratio generally has a value that is close to unity; approximately between the 0.98 and 0.998. Alpha and beta are more precisely related through the following identities (NPN transistor):

αF = Ic/IE

βF = Ic/IB

βF = αF / (1- αF) ↔ αF = βF / (βF +1)


Related Discussions:- Storage delay and transistor alpha- beta

The resistance of an 8 m length of the same wire, The resistance of a 5 m l...

The resistance of a 5 m length of wire is 600Ω.Determine: a)  the resistance of an 8 m length of the same wire, b)  the length of the same wire when the resistance is 420Ω

24 - outlet uni-selector, In this case, 24 simultaneous calls can be put th...

In this case, 24 simultaneous calls can be put through switch. Generally a 24-outlet Uni-selector is used as a selector hunter. Every one of the 24 outlets is connected to one two-

Write short note on quantization, Q. Write short note on Quantization? ...

Q. Write short note on Quantization? Quantization: This is first step in PCM. Total amplitude range of the modulating signal is divided into a number of standard levels calle

Analog averaging system, Consider the analog averager where x(t) is the inp...

Consider the analog averager where x(t) is the input and y(t) is the output. (a)   Find the impulse response h(t) of the average.  Is this system causal? (b)   Let x(t)

Segment is used to store interrupt, Which Segment is used to store interrup...

Which Segment is used to store interrupt and subroutine return address registers? Ans) Stack Segment in segment register is used to kept interrupt and subroutine return address

Dc motor starting, DC Motor Starting When voltage is applied to the arm...

DC Motor Starting When voltage is applied to the armature of a dcmotorwith the rotor stationary, no emf is generated and the armature current is limited only by the internal ar

What minimum value of coupling resistance, Q. It is desired to have a sag o...

Q. It is desired to have a sag or tilt of no more than 10% when a 50Hz square wave is impressed on an amplifier stage. The output circuit resistance is Rv=1K. What minimum value of

Role of a bus arbiter in a multiprocessor configuration, Discuss the role o...

Discuss the role of a bus arbiter in a multiprocessor configuration. Bus arbiter: It functions to resolve priority among bus masters and permits only one device at a time to

Explain series capacitors, Explain Series capacitors These are connecte...

Explain Series capacitors These are connected in series with the line conductors and are used to reduce the inductive reactance of long transmission lines and hence the voltage

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd