Daniel San
Newbie level 3
1. The problem statement, all variables and given/known data
Given the following circuit find the input resistance as seen through vo.
2. Relevant equations
3. The attempt at a solution
To solve this problem I started by drawing the signal equivalent circuit:
As we can see the voltage vgs = vi - vo. To find the input resistance I used Thenevin's theorem, placing a DC test voltage, VT, between the output terminals. By finding the relationship between VT and the current that passes throught it I hoped to find the value of the input resistance.
This, however, didn't take me to the correct result. I was told the result was equal to 1/gm || ro || Rs. I do not understand how to get to this result tho.. If someone could point me in the right direction I'd appreciate!
Given the following circuit find the input resistance as seen through vo.
2. Relevant equations
3. The attempt at a solution
To solve this problem I started by drawing the signal equivalent circuit:
As we can see the voltage vgs = vi - vo. To find the input resistance I used Thenevin's theorem, placing a DC test voltage, VT, between the output terminals. By finding the relationship between VT and the current that passes throught it I hoped to find the value of the input resistance.
This, however, didn't take me to the correct result. I was told the result was equal to 1/gm || ro || Rs. I do not understand how to get to this result tho.. If someone could point me in the right direction I'd appreciate!