# Darlington Pair/ Darlington Transistor

• Larrytsai
In summary, darlington transistors are used to amplify weak signals and consist of two transistors connected in a way that allows for increased amplification. The collectors of the transistors are connected together and there is also a variation called the Sziklai pair that may have advantages.
Larrytsai
Hey guys,

I just found out about these darlington transistors, and I read that the purpose of these transistors are to "amplify WEAK signals".

After taking a look at the circuit diagram for the darlington pairs, it seems to me that it is just 2 npn bjts with one of the bjt's emitter connected to the base of the other. Well I was wondering is this how you make a darlington pair?, you just get 2 bjts and connect one emitter to the base of the other?

Larrytsai said:
After taking a look at the circuit diagram for the darlington pairs, it seems to me that it is just 2 npn bjts with one of the bjt's emitter connected to the base of the other. Well I was wondering is this how you make a darlington pair?, you just get 2 bjts and connect one emitter to the base of the other?
No, the transistors should have their collectors connected together as well. It is also possible to have a PNP Darlington pair.

It's worth noting that the http://en.wikipedia.org/wiki/Sziklai_pair" may have advantages over the Darlington Pair.

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## What is a Darlington Pair/ Darlington Transistor?

A Darlington Pair, also known as a Darlington Transistor, is a circuit configuration that consists of two bipolar transistors connected together. This configuration provides a high current gain and is commonly used in applications where a small input current needs to control a larger load current.

## How does a Darlington Pair/ Darlington Transistor work?

In a Darlington Pair, the two transistors are connected in a way that the output of the first transistor is the input of the second transistor. This results in a combined current gain of the two transistors, which is the product of the individual current gains. This allows for a small input current to control a larger output current.

## What are the advantages of using a Darlington Pair/ Darlington Transistor?

The main advantage of using a Darlington Pair is its high current gain. It also has a high input impedance and low output impedance, making it suitable for driving low impedance loads. Additionally, it has a low saturation voltage, which reduces power dissipation and heat generation.

## What are the common applications of a Darlington Pair/ Darlington Transistor?

Darlington Pairs are commonly used in applications where a small input current needs to control a larger load current, such as in motor control circuits, switching power supplies, and audio amplifiers. They are also used in high voltage and high power applications due to their ability to handle large currents.

## What are the limitations of a Darlington Pair/ Darlington Transistor?

One limitation of a Darlington Pair is its relatively slow switching speed compared to a single transistor. This can cause issues in applications that require fast switching. Additionally, it has a higher input voltage requirement and a higher voltage drop, which may not be suitable for low voltage applications.

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