Storage delay and transistor alpha- beta, Electrical Engineering

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)

Posted Date: 1/10/2013 6:38:25 AM | Location : United States







Related Discussions:- Storage delay and transistor alpha- beta, Assignment Help, Ask Question on Storage delay and transistor alpha- beta, Get Answer, Expert's Help, Storage delay and transistor alpha- beta Discussions

Write discussion on Storage delay and transistor alpha- beta
Your posts are moderated
Related Questions

Q. For the circuit of Figure: (a) Find an expression for the power absorbed by the load as a function of RL. (b) Plot the power dissipated by the load as a function of the lo

Explain the operation of 8279.  Explain the following terms: (i)  N key Roll over. (ii)  Key board debounce. (iii)  FIFO RAM. Ans The 8279 microprocessor i

Compare dispersion effects in single mode and multimode fibres? The optical fibres were categorized within two according to the number of modes it passes as: • Single mode fibre

Q. Sinusoidal steady-state phasor analysis? The kind of response of a physical system in an applied excitation depends in general on the type of excitation, the elements in the

Uninterruptable power  Supply An uninterruptible  power supply  provides emergency power when  utility power  is not  available. It  maintains the supply  under  all condition


Which clipper would you prefer between the series and the shunt clipper? Why?

what is a armature reaction ?? give some concepts on double rotating field theory?? thanks

Q. Consider an RC parallel circuit excited by (a) i(t) = 20e -2t A, and (b) i(t) = 20 A. Find the forced component of the current through the capacitor for R = 2  and C = 2F.