A combined structure in which the current amplified by one bipolar transistor is again subjected to be amplified by the second bipolar transistor. The Darlington transistors are made up of two PNP or NPN BJTs by connecting together. The emitters of the PNP transistor are connected to the base of the other PNP transistor to create a sensitive transistor with high current gain. It is used in many applications where switching or amplification is crucial.
