2-7
We now have a properly biased NPN transistor.
In summary, the base of the NPN transistor must be positive with respect to the emitter, and the
collector must be more positive than the base.
NPN FORWARD-BIASED JUNCTION.—An important point to bring out at this time, which was
not necessarily mentioned during the explanation of the diode, is the fact that the N material on one side of
the forward-biased junction is more heavily doped than the P material. This results in more current being
carried across the junction by the majority carrier electrons from the N material than the majority carrier
holes from the P material. Therefore, conduction through the forward-biased junction, as shown in figure
2-5, is mainly by majority carrier electrons from the N material (emitter).
