Question 4: In the series-shunt feedback amplifier shown in Figure 3, the transistors are biased with ideal current-sources ₁ = 0.1 mA and I₂ = 0.1mA, the devices operate with VBE= 0.7V and ₁= B₂ = 120. The input signal V has a zero DC component. Resistances are R = 1000, R₁ = 1kN, R₂ = 10kN, R₁ = 1kN. b) Find the DC emitter current in each of Q1 and Q2 and the DC voltage at the emitter of Q2. c) Sketch the open-loop circuit without the DC sources. Derive expressions for A,Ri, and Ro, and find their values. [4 marks] d) Find the closed-loop gain Aƒ = V/V, the input resistance Rin, the output resistance Rout. a) If the open loop gain is large, what do you expect the closed-loop gain Af = V₁/V₂ to be? Give both an expression and its approximate value.