Environmental Engineering Reference
In-Depth Information
By inspection of fig. 6.18 we easily find that the current entering into
terminal X of transistor T2 is equal to
hence, neglecting resistance
we get
Therefore, substituting (6.32), (6.35) and (6.37) into the Rosenstark
relationship, exact expression of the closed loop gain of shunt-series
feedback amplifier can be found. For practical cases where the loop gain is
much greater than one, the closed loop gain is very well approximated by the
asymptotic one.
Finally, we have to calculate the resultant input and output resistances
through terms
and
From (6.35) we can
simply calculate
and
whose expressions are
