http://www.futureelectronics.com/en/Search.aspx?dsNav=Ny:True,Nea:True,N:675 , Well explain what is a Darlington Transistor & how to select the right one for your application from our line-up of Darlington Transistor products. A Darlington transistor consists of a pair of bipolar transistors that are connected to provide a very high current gain from a low base current. The current is amplified by the first transistor and amplified further by the second one. http://youtu.be/wMBCb_iB0bk