___________________________________________________________________________ Transistors
COMMON BASE CONFIGURATION -
mainly used for impedance
matching,
since it has a low input resistance and a high output resistance. It also has a
current gain of less than 1. In the CB, the input is applied to the emitter, the
output is taken from the collector, and the base is the element common to input
and output.
COMMON COLLECTOR CONFIGURATION - used as a current driver for
impedance matching and is particularly useful in switching circuits. The CC is
also referred to as an emitter-follower and is equivalent to the electron-tube
cathode follower. Both have high input impedance and low output impedance.
In the CC, the input is applied to the base, the output is taken from the emitter,
and the collector is the element common to input and output.
23 June 2005
TC 9-62
2-43