//Tested on Windows 7 Ultimate 32-bit //Chapter 8 Power Amplifiers Pg no. 277,278 and 279 clear; clc; //Given Data //Figure 8.13 VCC=20;//collector supply voltage in volts RC=270;//collector resistance in ohms RE=150;//emitter resistance in ohms R1=3.3D3;//divider network resistance R1 in ohms R2=1.5D3;//divider network resistance R2 in ohms VBE=0.7;//forward voltage drop of emitter diode in volts B=100;//DC CE current gain beta RL=470;//load resistance in ohms C1=15D-6;//input coupling capacitance in farads C2=15D-6;//output coupling capacitance in farads //Solution VB=VCC*R2/(R1+R2);//base to ground voltage in volts VE=VB-VBE;//emitter to ground voltage in volts IE=VE/RE;//emitter current in amperes ICQ=IE;//neglecting base current, collector current is equal to emitter current in amperes VC=VCC-ICQ*RC;//collector to ground voltage in volts VCEQ=VC-VE;//collector to emitter quiscent voltage in volts PD=VCEQ*ICQ;//power dissipation in watts RL_dash=RC*RL/(RC+RL);//equivalent a.c. load resistance in ohms IC_sat=ICQ+VCEQ/RL_dash;//saturation collector current in amperes VCE_cutoff=VCEQ+ICQ*RL_dash;//cutoff collector to emitter voltage in volts Pout=0.5*ICQ^2*RL_dash;//output a.c. power in watts e=Pout/VCC/ICQ;//efficiency of circuit = Pout/Pin(dc) printf("(a) The minimum transistor power rating required PD = %.3f Watts\n ",PD); printf("(b) AC output power Pout = %d milli-Watts\n ",Pout*10^3); printf("(c) Efficiency of the amplifier η = %.2f\n ",e); //decimal approximation taken here in efficiency