3.3 TRANSISTOR OPERATION
The basic operation of the transistor will now be described using the pnp transistor
of Fig. 3.2a. The operation of the npn transistor is exactly the same if the roles played
by the electron and hole are interchanged. In Fig. 3.3 the pnp transistor has been redrawn
without the base-to-collector bias. Note the similarities between this situation
and that of the forward-biased diode in Chapter 1. The depletion region has been reduced
in width due to the applied bias, resulting in a heavy flow of majority carriers
from the p- to the n-type material.