miller effect in bjt
The feedback connection of between base and collector
causes it to appear to the amplifier like a large capacitor
has been inserted between the base and emitter terminals. This
phenomenon is called the ?Miller effect? and the capacitive multiplier
?1 ? K ? acting on equals the common emitter amplifier mid-band
gain, i.e. .
Common base and common collector amplifiers do not suffer
from the Miller effect, since in these amplifiers, one side of
is connected directly to ground.
more details:
miller-effect-lecture-notes.pdf