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+// Example1.4 : Bipolar junction transistor
+
+// 1,4a
+// using voltage divider rule the fraction of input signal v_be=v_s*r_pi/(r_pi+R_s)
+// output voltage v_o=-g_mv_be(R_L||r_o)
+r_pi=2.5*10^3; // (ohm)
+R_s=5*10^3; // (ohm)
+R_L=5*10^3 // (ohm)
+g_m=40*10^-3; // (mho)
+r_o=100*10^3; // (ohm)
+gain=-(r_pi*g_m*(R_L*r_o/(R_L+r_o)))/(r_pi+R_s); // gain=v_o/v_s
+disp(gain,"The voltage gain (V/V) =")
+gain_negl_r_o=-r_pi*g_m*R_L/(r_pi+R_s);
+disp(gain_negl_r_o,"Gain neglecting the effect of r_o (V/V) =")
+
+// 1.4b
+// Bi_b=g_m*v_be
+// B is short circuit gain
+B=g_m*r_pi;
+disp(B,"The short circuit gain (A/A) =")
+\ No newline at end of file