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

Slip-power controlled wound-rotor induction-motor drives, Q. Slip-power con...

Q. Slip-power controlled wound-rotor induction-motor drives? Slip power is that portion of the air-gap power that is not converted into mechanical power. The methods involving

Thevenin theorem, advantages and disadvantages of thevenin theorem

advantages and disadvantages of thevenin theorem

Clipper and clamper circuit, Clipper Circuits: Clipper circuit have ab...

Clipper Circuits: Clipper circuit have ability to Clipper of portions of the input signals without distorting the remaining part of the alternating wave form. Clamper net

Define wireless communications, Q. Define wireless communications? The ...

Q. Define wireless communications? The latest wireless communications technology is the personal satellite phone. The coverage is planetary and one can reach anywhere on earth.

Explain the electrical contact materials with examples, Explain the electri...

Explain the electrical contact materials with examples. Electrical contact materials: A number of elements in their pure form as copper, nickel, palladium, molybdenum, platin

Compute efficiency of 4 hours full load at 0.8 power factor, Q. A 10-kVA tr...

Q. A 10-kVA transformer is known to have an iron loss of 150 W and a full-load copper loss of 250 W. If the transformer has the following load cycle, compute its all-day efficiency

Explain working of liquid-crystal display, Q. Explain Working of Liquid-cry...

Q. Explain Working of Liquid-crystal display? This display needs only microwatts of power (over a thousand times less than a LED) and is used in such devices as electronic wris

Illustrate the principle of alignment, Q. Illustrate the principle of align...

Q. Illustrate the principle of alignment? Pieces of highly permeablematerial, such as iron, situated in ambientmediumof lowpermeability, such as air, in which a magnetic field

Evaluate a single-stage transistor amplifier, Design and using Pspice, eval...

Design and using Pspice, evaluate a single-stage transistor amplifier amplifier to meet the following specifications: * Power supply - 12V dc. · *Voltage gain - 120 when Vin

Why digital signal processing require specialized hardware, Why does digita...

Why does digital signal processing require specialized hardware? A) It needs to perform analog as well as digital functions. B) General-purpose microprocessors cannot perfor

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