School of Computer Science and Electrical Engineering 17/05/01 The bipolar Junction Transistor The term Bipolar is because two type of charges (electrons and holes)are involved in the flow of electricity The term Junction is because there are two pn unctions There are two configurations for this device n-type p-type n-type p-type n-type p-type Symbol NPN PNP Lecture 11 ENG1030 Electrical Physics and Electronics B./T DownsENG1030 Electrical Physics and Electronics B.Lovell/T.Downs School of Computer Science and Electrical Engineering 1 17/05/01 Lecture 11 The Bipolar Junction Transistor • The term Bipolar is because two type of charges (electrons and holes) are involved in the flow of electricity • The term Junction is because there are two pn junctions • There are two configurations for this device n-type p-type n-type NPN Symbol b e c p-type n-type p-type PNP Symbol b c e