Hey all. I have been trying to calculate the input resistance of a common gate amplifier, but seem to have problems doing so.(adsbygoogle = window.adsbygoogle || []).push({});

I know I have to set a test voltage (or test current) at the input, and I've been told, to ground the output. So using the Hybrid pi model for a mosfet, I did the following to calculate the input resistance:

I apologize for my low quality picture. Please any help or hints are greatly appreciated. I just don't know what I am doing wrong. I have used the exact same technique on other amps and it seems to have worked fine, just not with common gates amps : (

Thank you.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Input Resistance of Common Gate question...

Loading...

**Physics Forums | Science Articles, Homework Help, Discussion**