The circuit in given Figure is the ac equivalent circuit of a series-series feedback amplifier.
Assume that the bias circuit, which is not shown, results in quiescent collector currents of IC1 = 0.5 mA, IC2 = 1 mA, and IC3 = 2 mA.
Assume transistor parameters of hF E = 120 and ro = ∞. Determine the transconductance transfer function Ag f = Io/Vs.