Environmental Engineering Reference
In-Depth Information
Assume as control parameter
P
the transconductance of the transistor,
Hence, the controlling variable (denoted before as is voltage and the
controlled variable is the current of the controlled generator. Setting
parameter
P
equal to zero means switching off the controlled current source.
By evaluating under this condition the transfer gain of the amplifier we
found the direct gain In particular, the voltage at node X is due to a
partition of the input signal,
Consider the controlled current source an independent current source,
P =
and set to zero (i.e. shorting) the input signal generator. Now evaluate the
voltage
due to the independent current source,
P,
Hence, changing the sign and multiplying for the transconductance value we
obtain the return ratio
Finally, set control parameter,
P,
equal to infinity. The controlled current
source is finite, and this means that the control variable,
must be equal to
zero. Hence,
and the asymptotic gain results
