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+//Example 1.27
+clc
+disp("Step 1: Identity topology")
+disp("The feedback is given from emitter of Q2 to the base of Q2. If Io=0 then feedback current through 5K register is zero, hence it is current sampling. As feedback signal is mixed in shunt with input, the amplifier is current shunt feedback amplifier")
+disp("")
+disp("Step 2 and Step 3: Find input and output circuit")
+disp("The input circuit of the amplifier without feedback is obatined by opening the output loop at the emitter of Q2(Io = 0). This places R''(5K) in series with R_s from base to emitter of Q1. The output circuit is found by shorting the input node, i.e. making V1=0. This places R''(5K) in parallel with R_e. The resultant equivalent circuit is shown in fig 1.78")
+disp("Step 4: Find open circuit transfer gain")
+disp("A_I = Io/I_s = -I_c/I_s = -I_c2/I_b2 * I_b2/I_c1 * I_c1/I_b1 * I_b1/I_s")
+disp("We know that  -I_c2/I_b2 = A_i2 = -h_fe = -50 and")
+disp("-I_c/I_b1 = A_i1 = -h_fe = -50")
+disp("Therefore,  I_c1/I_b1 = 50")
+disp("Looking at fig 1.77 we can write")
+disp("I_b2/I_c1 = -R_c1/R_c1+R_i2")
+ri2=1.5+(51*(5*0.6/5.6))
+format(6)
+disp(ri2,"R_i2(in k-ohm) = h_ie + (1+h_fe)(R_e2||R'') =")
+ibc=-2/30.82
+format(7)
+disp(ibc,"Therefore,  I_b2/I_c1 =")
+disp("Looking at fig 1.78 we can write")
+disp("I_b1/I_s = R/R+R_i1")
+r=(5.6*10^3)/6.6
+format(4)
+disp(r,"where  R(in ohm) = R3 || (R''+R_e) =")
+ri1=1.5+20.4
+format(5)
+disp(ri1,"and  R_i1(in k-ohm) = h_ie + (1+h_fe)R_e1 =")
+ib1=0.848/22.748
+format(7)
+disp(ib1,"Therefore,  I_b1/I_s =")
+disp("Substituting the numerical values obtained in equations of A_I we get,")
+ai=50*0.0649*50*0.0372
+format(2)
+disp(ai,"A_I =")
+disp("")
+disp("Step 5: Calculate beta")
+b=0.6/5.6
+format(6)
+disp(b,"beta = I_f/Io = R_e2 / R_e2+R'' =")
+disp("")
+disp("Step 6: Calculate D,A_If, A_vI, R_sf, R_of")
+d=1+(0.107*6)
+format(6)
+disp(d,"D = 1 + beta*A_I =")
+aif=6/1.642
+disp(aif,"A_if = A_I/D =")
+avf=(3.654*12)/1
+format(7)
+disp(avf,"A_vf = Vo/V_s = -I_c2/I_s * R_c2/R_s = A_if*R_c2 / R_s =")
+ri1=(848*21900)/(21900+848)
+disp(ri1,"R_i1(in ohm) = R || R_i1 =")
+rif=816.38/1.642
+format(6)
+disp(rif,"R_if(in ohm) = R_i/D =")
+disp("Ro = infinity    because h_oe = 0")
+disp("Therefore,  R_of = Ro*D = infinity")
+disp("R''_o = Ro || R_c2 = infinity || 12 K = 12 K")
+disp("R''_of = R''_o * 1+beta*A_i/1+beta*A1 = R''_o = R_c2 = 12K")