Assignment:
Find values for the resistances shown in the circuit below such that the circuit behaves as a difference amplifier with an input resistance of 30 kohms and a gain of 80.
a. R1=R3 = 10 k, R2=R4 = 1.0M
b. R1=R3 = 15 k, R2=R4 = 1.0M
c. R1=R3 = 15 k, R2=R4 = 1.2M
d. R1=R3 = 17 k, R2=R4 = 1.4M