How to calculate gain and output impedance?

[RogerGustavsson]

I would like to know how to calculate voltage gain and output
impedance in a few impedance converters.

Please, look at the questions and the schematics here:

http://twin-x.com/groupdiy/displayimage.php?pos=-2345
http://twin-x.com/groupdiy/displayimage.php?pos=-2344


Roger

 

[oldeurope]

#1

Hello Roger,
seems ok to me.
For the cascode take gm of the bottom transistor, same calculation like above.

Try a bipolar transistor. You'll be surprised! gm = Ie/UT

gm = transconductance
Ie = DC Emitter current
UT = 40mV (silicon)

Darius