How do we calculate an amp's input and output impadance?

[Bricolo]

According to the shematic, not with measurements


thanks

[uli]

Hi,
assuming we´re talking about MOSFET amplification I would
calculate as follows: Input impedande of a non inverting input is
about the value of the input resistor to ground, as the fet´s input impedance is that high that you need not take it into account in
real life. Inverting input with feed back: about the amount of the
series resistor in the signal path, as the input impedance of the DUT is about zero.
Output: A bit complicated but I do it like this: On resistance of the
FET plus Source resistor plus Outputimpedance of the power supply divided thru the amount of feedback (open loop amplification´thru closed loop amplification.

Uli