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//Tested on Windows 7 Ultimate 32-bit
//Chapter 6 Single Staje BJT Amplifiers Pg no. 197
clear;
clc;
//Given Data
//Figure 6.18,6.19,6.20
VCC=15;//collector supply voltage in volts
RC=5.6D3;//collector resistance in ohms
RE0=390;//unbypassed emitter resistance in ohms
RE1=390;//bypased emitter resistance in ohms
R1=33D3;//divider network resistance R1 in ohms
R2=4.7D3;//divider network resistance R2 in ohms
VBE=0.7;//forward voltage drop of emitter diode in volts
Bdc=140;//DC CE current gain beta
Bac=160;//AC CE current gain beta
VT=25D-3;//voltage equivalent of temperature in volts
Vs=15D-3;//source rms voltage in volts
Rs=600;//source internal impedance in ohms
C1=10D-6;//input coupling capacitance in farads
C2=50D-6;//emitter bypass capacitance in farads
C3=10D-6;//output coupling capacitance in farads
RL=68D3;//load resistance in ohms
//Solution
Rin_dc=Bdc*(RE0+RE1);//dc input resistance in ohms
if 0.1*Rin_dc>R2 then
VB=VCC*R2/(R1+R2);//base to ground voltage in volts , since Rin>10*R2 it can be neglected
end
VE=VB-VBE;//emitter to ground voltage in volts
IE=VE/(RE0+RE1);//emitter current in amperes
IC=IE;//collector current is approximately equal to emitter current
VC=VCC-IC*RC;//collector to ground voltage in volts
re=VT/IE;//equivalent BJT model emitter resistance in ohms
Rin_dash=Bac*(RE0+re);//internal resistance of BJT in ohms
Rin=1/(1/R1+1/R2+1/Rin_dash);//total internal resistance is Rin=R1||R2||Rin'
Vb=Rin/(Rs+Rin)*Vs;//signal voltage at base in volts
Ib=Vb/Rin_dash;//base current due to source
Is=Vs/(Rin+Rs);//current driven from source in amperes
Ic=Bac*Ib;//collector a.c. current
Gi_dash=Ic/Is;//overall a.c. current gain
RL_dash=RC*RL/(RC+RL);//a.c. value of collector resistance in ohms
Gv=RL_dash/re;//a.c. voltage gain
f=Rin/(Rs+Rin);//input attenuation factor
Gv_dash=f*Gv;//overall a.c. voltage gain
Gp_dash=Gv_dash*Gi_dash;//a.c. power gain
printf("Current gain Gi'' = %.2f and power gain Gp'' = %.2f",Gi_dash,Gp_dash);
//error in calculation and missing calculation of power gain in textbook
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