What is a darlington pair, Electrical Engineering

Assignment Help:

Q. What is a darlington pair?

                            The Darlington circuit consists of two cascaded emitter followers with infinite emitter resistance in the first stage.here the two transistor form a composite pair, input impedance of the second transistor consisting of the emitter load resistance of the first transistor.

· Darlington emitter follower has high input impedance than the single stage emitter follower.

· Its voltage gain is less close to unity than a single stage emitter follower.

· The output impedance of a darlington circuit may be greater than or less than that of a single transistor emitter follower, depending upon the value of resistance.

· Major drawback of Darlington transistor pair is that the leakage current of the first transistor is amplified by the second; hence the overall leakage current is high. A Darlington pair is two transistors connected together to give a very high current gain. In addition to standard (bipolar junction) transistors, there are field-effect transistors which are usually referred to as FETs.

1806_What is a darlington pair.png

 

The emitter current of Tr1 is the base current of Tr2.

A change in base current of Tr1 can give a change 100 times larger in its emitter current. A change in the base current of Tr2 has a similar effect on its emitter current. Therefore there is an overall amplification of 100 x 100 = 10000 times. This circuit is sometimes called the Super Alpha Pair. It is often used as a power output stage.


Related Discussions:- What is a darlington pair

Determine the self inductance of the two coils, Determine the self inductan...

Determine the self inductance of the two coils: Two coils with a coefficient of coupling of 0.6 between them are connected in series so as to magnetize (i) in the same directi

Clippers, Which clipper would you prefer between the series and the shunt c...

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

Describe the functionalities and the purpose of an equalizer, Question: ...

Question: (a) For a CD quality sound, what is the bit depth used and give the amplitude's levels and the dynamic range of this sound quality (b) In audio technology, the dec

Inductor, What will I write in Inductor conclusion

What will I write in Inductor conclusion

Shunt reactor, what are the basic principles of shunt reactor and it''s ope...

what are the basic principles of shunt reactor and it''s operation system

Compute the ensemble mean and standard deviation, Write three m ?les to gen...

Write three m ?les to generate M ensemble members of length N, for the following three random processes: i) function v=rp1(M,N); a=0.02; b=5; Mc=ones(M,1)*b*sin((1:N)*p

Compute the minimum line current for the motor, A three-phase, wye-connecte...

A three-phase, wye-connected, four-pole, 400- V, 60-Hz, 15-hp synchronous motor has a synchronous reactance of 3  per phase and negligible armature resistance. The data for its no

Mid band voltage gain, For the amplifier circuit shown below estimate the m...

For the amplifier circuit shown below estimate the mid band voltage gain if the EARLY voltage (V A ) of the current mirror transistors is 80 volts.  Assume the d.c biasing is optim

Define the time constant of the circuit, A coil of inductance 0.04 H and re...

A coil of inductance 0.04 H and resistance 10? is connected to a 120 V, d.c. supply. Verify (a)  The final value of current     (b)  The time constant of the circuit (c)

What is tri-state logic, Three Logic Levels are used and they are High, Low...

Three Logic Levels are used and they are High, Low, High impedance state. The high and low are normal logic levels & high impedance state is electrical open circuit conditions. Tri

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