Determine the small-signal parameters for q1nbspand q2

Question

The circuit in given figure is an example of a shunt-series feedback circuit. A signal proportional to the output current is fed back to the shunt connection at the base of Q₁.

However, the circuit may be used as a voltage amplifier.

Assume transistor parameters of h_F E = 120, V_B E (on) = 0.7 V, and V_A = ∞.

(a) Determine the small-signal parameters for Q₁ and Q₂.

(b) Using nodal analysis, determine the small-signal voltage gain A_v = v_o/v_s.