Referring to data sheet at http://www.fairchildsemi.com/ds/MM/MMBFJ201.pdf
The Yfs for the 202 device is 1000umhos. How do I go about calculating the gain
of a jfet circuit?

 

Give this a read:

http://www.electronics-tutorials.ws/amplifier/amp_3.html

 

Thanks, I appreciate the information.