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What is the input impedance of Darlington Pair transistor?
A typical Darlington transistor has a current gain of 1000 or more, so that only a small base current is needed to make the pair switch on higher switching currents. Another advantage involves providing a very high input impedance for the circuit which also translates into an equal decrease in output impedance.
How does a Sziklai pair differ from a Darlington Pair?
The Sziklai Pair uses transistors of complementary polarity to achieve the same gain as the Darlington Pair, but with improved VBE characteristics. Only Q1’s base-emitter junction is exposed to the outside world. However, the Sziklai pair does not suffer as badly as the Darlington in terms of VBE.
Why does Darlington Pair have high input impedance?
6 The Darlington Pair. The effect of a high input impedance is to reduce the input current to the amplifier. If the input current for a given input voltage is reduced by whatever method, the effect is to increase the input impedance.
Why is a Darlington connection of three or more transistors usually impractical?
Disadvantages of Darlington Transistor It has a slow switching speed. The base-emitter voltage is almost two times compared to a normal transistor. Due to high saturation voltage, in such an application, it dissipates high power. The bandwidth is limited.
What is the purpose of a Darlington pair?
The Darlington transistor pair is a very useful circuit in many applications. It provides a high level of current gain which can be used in many power applications. Although the Darlington pair has some limitations, it is nevertheless used in many areas, especially where high frequency response in not needed.
What are the advantages of a Darlington pair?
Benefits or advantages of Darlington transistor ➨It offers very high current gain in comparison to single transistor. ➨It offers very high input impedance. ➨It uses few components and hence can be used for easy circuit designs. ➨It can amplify signal to larger extent.
How is the Darlington circuit similar to the Sziklai pair?
The Sziklai pair circuit utilises a very similar topology to that of the Darlington and it provides a similar beta boosting configuration to provide very high levels of gain. Like the Darlington, the Sziklai pair uses two transistors with the collector of the first transistor being connected directly to the base of the second.
How many transistors are in a Sziklai pair?
In electronics, the complementary feedback pair, also known as a Sziklai pair, is a configuration of two bipolar transistors, similar to a Darlington pair. In contrast to the Darlington arrangement, the complementary feedback pair has one NPN and one PNP transistor, and so it is sometimes also called…
What are the uses of the Sziklai pair?
Possibly the most common areas are in audio output stages where it can be used as one half of a push pull amplifier, the other half being a Darlington. In this way the Sziklai pair enables the output to operate in a complementary symmetry fashion. The Sziklai pair also finds uses in a number of digital circuits.
Can a Darlington be used as a complementary pair?
Only a single base emitter drop between the overall base and emitter of the compound transistor. Higher saturation voltage than a Darlington. Can be used in a pseudo-complementary output with a Darlington – a true complementary pair would use both of the same circuit configurations.