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

Literature review - software defined radio, Literature Review - Software De...

Literature Review - Software Defined Radio In this section, first two methods to estimate signal to noise ratio (SNR) are reviewed and a few methods for modulation classificati

Determine the armature current and torque angle, Q. Determine the armature ...

Q. Determine the armature current and torque angle? A 1500-hp, 6600-V, six-pole, 60-Hz, three-phase, wye-connected, synchronous motor, with a synchronous reactance of 36 , neg

Give the classification of oscillators, Q. Give the classification of oscil...

Q. Give the classification of oscillators. Discuss the frequency stability of oscillators. Oscillators are classified in the following different ways. 1. According to the wa

Rectifier, the forward resisitance of a semi conductor diode is 10 ohm, two...

the forward resisitance of a semi conductor diode is 10 ohm, two such diodes used in full wave rectifier subjectto a sinusoidal voltage wave form. given by v(t)=308 , sin(100 pi t)

Which realization requires the least number of gates, Q. Consider a 1-bit v...

Q. Consider a 1-bit version of the digital comparator shown in Figure. Note that the operation of this circuit is such that whichever output is 1 gives the desired magnitude compar

Level4, What are the three modes of operation of rotating machines

What are the three modes of operation of rotating machines

Dc motor - motor control , DC Motor The motor  which  require dc  supp...

DC Motor The motor  which  require dc  supply to drive them are called DC motors DC motor  consist  two types  of windings. a. Fields Winding b. Armature Winding

Elementary induction machines, Elementary Induction Machines In the dis...

Elementary Induction Machines In the discussion that followed Equation, the third possiblemethod of producing constant torque was to cause the mmf axes of stator and rotor to r

Compute the motor speed, Consider the 220-V, 1800-r/min dc motor, controlle...

Consider the 220-V, 1800-r/min dc motor, controlled by a three-phase fully controlled rectifier from a 60-Hz ac source. The armature-circuit resistance and inductance are 1.5  and

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