Semiconductor Fundamentals Unit 5 – Transistor Junctions & PNP DC Bias
The PNP transistor shown has the base and collector terminals negative with respect to the
emitter terminal. Because the negative (N) base material has a more negative voltage than the
emitter, the PN junction is forward biased and permits current to flow from the base to the
emitter. The current arrows indicate electron current flow. The base current permits collector
current to flow to the emitter because the collector is more negative than the emitter.
The NPN transistor shown has the base and collector terminals positive with respect to the
emitter terminal. Because the positive (P) base material has a more positive voltage than the
emitter, the PN junction is forward biased and permits current to flow from the emitter to the
base. The base current permits collector current from the emitter because the collector is more
positive than the emitter.