[sdiy] Single transistor Class A input/Output Impedance?

[Phil Macphail]

On 22/02/2014 15:43, "Justin Owen" <juzowen at gmail.com> wrote:

>
>
>So in the schem I linked to, with e.g. a 1Meg R to GND in front of C1 -
>let's call it Rm - would that affect input Z?
>
>Would the calculation then be  Rm || R1 || R2 ?
>
>Thanks - appreciated.
>
>- J

Rm || R1 || R2 || (hfe*(re+Re)) would be more correct, but still neglects
any AC or large-signal effects. Perhaps you need a better textbook if it
is missing the formulae to go with the diagram! :-)


Phil.
>