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

Synchronization, Synchronization:  Whatever type of weep is used, it must ...

Synchronization:  Whatever type of weep is used, it must be synchronized with the signal being measured. Synchronization has to be done to obtain a stationary pattern. This requir

Unconditional jump - jump instruction , Unconditional Jump JMP ( Uncon...

Unconditional Jump JMP ( Unconditional Jump ) Instruction: This  instruction is used to transfer  the execution to the  specified  memory  address unconditionally ( does not c

Define byte assembler directive, What do you understand by DB assembler...

What do you understand by DB assembler directive?   DB (Define Byte): The DB directive explains by a byte-type variable (that is a variable that occupies one byte of memo

Explain the synchronous machines, Explain the Synchronous Machines? A s...

Explain the Synchronous Machines? A synchronous machine, unlike an induction (or asynchronous) machine, only develops torque at a fixed, so called, synchronous speed - n s whi

Electrical fundamentals, Electrical Fundamentals 1. An aircraft compan...

Electrical Fundamentals 1. An aircraft company has decided to replace the copper cables to the main aircraft generators onboard it's Boeing 747s with aluminium cables that are

Representation of magnetic fields, The direction of the magnetic field line...

The direction of the magnetic field lines is given by 'Maxwell's Right-Hand corkscrew rule'  The thumb of the right hand indicates the direction of current flow in the wire and

Calculate the resistivity of an alloy of copper, The resistivity of pure co...

The resistivity of pure copper is 1.56 micro-ohm -cm.  An alloy of copper contains 1 atomic percent nickel has a resistivity of 2.81 micro-ohm-cm. An alloy of copper containing 3-

Give a general account of common drain amplifier, Q. Give a general account...

Q. Give a general account of common drain amplifier? The output is taken over the source terminal and when the dc supply is replaced by its short circuit equivalent, the drain

Define and explain numerical aperture, Define and explain Numerical apertur...

Define and explain Numerical aperture? Figure shown below shows an incident ray to the fibre, The light bends at two interfaces, one at the air- core interface and the

What is enhancement mosfets, Q. What is Enhancement MOSFETS? Figure ill...

Q. What is Enhancement MOSFETS? Figure illustrates the cross-sectional structure of an n-channel enhancement MOSFET and its symbol showing as a normally off device when used fo

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