Editing Darlington transistor (section)

==Darlington triplet==
A third transistor can be added to a Darlington pair to give even higher current gain, making a Darlington triplet.  The emitter of the second transistor in the pair is connected to the base of the third, as the emitter of first transistor is connected to the base of the second, and the collectors of all three transistors are connected together.  This gives current gain approximately equal to the product of the gains of the three transistors.  However the increased current gain often does not justify the sensitivity and saturation current problems, so this circuit is seldom used.