A darlington pair is a pair of transistors that are connected together in sunch a way to provide a very high current gain. A darlington pair is made by tying together the collectors of two transistors, and the emitter of transistor 1 to the base of transistor 2. The Base of transistor 1 becomes the base for the pair, and the emitter of transistor 2 becomes the emitter of the pair.
The Gain of the transistor is H1fe x H2fe
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