1. For the unity feedback system of Figure 1 with G(s) =- R(s) + E(s) K(s+6) s(s+1)(s+4) G(s) C(s) Figure 1 Determine the range of K to ensure stability. Find the value of K for marginal stability, and the frequency of oscillation under this condition.

R, OV OUT + Complete the analysis showing that Vo/Vin = -Rf/Rin Let currents be defined as 1 equals the current flowing through Rin from left to right 12 equals the current flowing into the Opamp 13 equals the current flowing through the feedback resistor from left to right. Write the KCL equation in terms of 11, 12, and 13 at the inverting node of the Op-Amp. O There is no current flowing in the circuit O 12 = 11 + 13 O 11 = 12 + 13 11 + 12 = 13