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

Express the waveform of the staircase type, Q. Express the waveform of the ...

Q. Express the waveform of the staircase type shown in Figure as a sum of step functions.

What do you mean by quartz crystals, Q. What do you mean by Quartz crystals...

Q. What do you mean by Quartz crystals? Synthetic quartz is composed of Silicon and Oxygen (Silicon Dioxide) and is cultured in autoclaves under high pressure and temperature.

Calculate the rated load current of machine, A 500 MVA, 33kv, three phase s...

A 500 MVA, 33kv, three phase steam turbine generator has a synchronous reactance of 1.6 p.u. It delivers a rated output at 0.8 power factor lagging. Calculate (a) The synchronou

Jfet applications, how is it possible to operate Q3 with no dc drain? where...

how is it possible to operate Q3 with no dc drain? where is the dc operating point?

Explain temperature effect on electrical conductivity metals, Explain the e...

Explain the effect of temperature on electrical conductivity of metals. As the temperature is increased, there is a greater thermal motion of atoms which decreases the regulari

Compute the induced emf, Compute the induced emf: If a coil of 150 tur...

Compute the induced emf: If a coil of 150 turns is linked with a flux of 0.01 wb while carrying a current of 10 Amp, compute the inductance of coil. Now, if current is reverse

Explain the transfer characteristics, Q. Explain the transfer characteristi...

Q. Explain the transfer characteristics in a few words ? The transfer characteristics are a plot of an output (or a drain) current versus an input controlling quantity. There i

Explain the excess three codes - bcd to decimal conversion, Explain the Exc...

Explain the Excess three codes - BCD to Decimal Conversion The Excess-3 representation of a number is based on Binary Coded Decimal. It is formed by taking the number in Binary

Show a schematic diagram of the seven- segment decoder, Q. Digital watches ...

Q. Digital watches display time by turning on a certain combination of the seven-segment display device. (a) Show a typical seven-segment display. (b) Develop a truth table f

What do you mean by heat sink?, Q. What is a heat sink? List the factors, w...

Q. What is a heat sink? List the factors, which determine its efficiency. To reduce the chance of thermal runaway, the rise of temperature at the collector junction to a danger

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