Page 134 - Testing Electronic Components

Testing Darlington Transistor

This is two transistors connected together of two emitter followers in
cascade so that the amplified current from the first is amplified further by
the second transistor. This package provides higher input resistance and a
very high current gain such as 10000. Darlington pairs are sold as
complete packages containing the two transistors. They have three leads
(Base, Collector and Emitter-PNP and NPN) which are equivalent to the
leads of a standard individual transistor. There are two types of
Darlington transistors-one that without a built in diode whiles the other
type has a diode in it. You have to refer to semiconductor data book to
check if the Darlington transistors have a built in diode or not.

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