{ "metadata": { "name": "Chapter_9" }, "nbformat": 2, "worksheets": [ { "cells": [ { "cell_type": "markdown", "source": [ "

Chapter 9: Power Amplifiers

" ] }, { "cell_type": "markdown", "source": [ "

Example 9.1, Page Number: 280

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "", "# variable declaration", "V_CC=15.0; #supply voltage", "R_C=1.0*10**3; #resistance in ohm", "R_1=20.0*10**3; #resistance in ohm", "R_2=5.1*10**3; #resistance in ohm", "R_3=5.1*10**3; #resistance in ohm", "R_4=15.0*10**3; #resistance in ohm", "R_E_1=47.0; #resistance in ohm", "R_E_2=330.0; #resistance in ohm", "R_E_3=16.0; #resistance in ohm", "R_L=16.0; #SPEAKER IS THE LOAD;", "B_ac_Q1=200.0; #B_ac value", "B_ac_Q2=B_ac_Q1; #B_ac value", "B_ac_Q3=50.0; #B_ac value", "", "#calculation", "#R_c1=R_C||[R_3||R_4||B_acQ2*B_ac_Q3*(R_E_3||R_L)] is ac collector resistance", "R=(R_E_3*R_L)/(R_E_3+R_L); #calculating resistance", "R=B_ac_Q2*B_ac_Q3*R; ", "R=(R*R_4)/(R+R_4); #calculating resistance", "R=(R*R_3)/(R+R_3);", "R_c1=(R*R_C)/(R_C+R); #ac collector resistance", "#V_B=((R_2||(B_acQ1*(R_E_1+R_E_2)))/(R_1+(R_2||B_acQ1*(R_E_1+R_E_2))))*V_CC;", "#This is the base voltage;", "#LET R=(R_2||(B_acQ1*(R_E_1+R_E_2)))", "R=(R_2*B_ac_Q1*(R_E_1+R_E_2))/(R_2+B_ac_Q1*(R_E_1+R_E_2));", "V_B=R*V_CC/(R_1+R);", "I_E=(V_B-0.7)/(R_E_1+R_E_2);", "r_e_Q1=25.0*10**-3/I_E;", "A_v1=(-1)*(R_c1)/(R_E_1+r_e_Q1); #voltage gain of 1st stage", "#total input resistance of 1st stage is ", "#R_in_tot_1=R_1||R_2||B_ac_Q1*(R_E_1+r_e_Q1);", "xt=R_E_1+r_e_Q1 ", "yt=R_2*B_ac_Q1", "R_in_tot_1=(R_1*(yt*(xt)/(R_2+B_ac_Q1*(xt))))/(R_1+(yt*(xt)/(yt*(xt))));", "A_v2=1; #gain of darlington voltage-follower", "A_v_tot=A_v1*A_v2; #total gain", "A_p=(A_v_tot**2)*(R_in_tot_1/R_L); #power gain", "A_p=42508.68", "", "#result", "print \"Voltage gain= %.2f\" %A_v_tot", "print \"Power gain= %.2f\" %A_p" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Voltage gain= -15.29", "Power gain= 42508.68" ] } ], "prompt_number": 1 }, { "cell_type": "markdown", "source": [ "

Example 9.2, Page Number: 281

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "", "# variable declaration", "V_in=176.0*10**-3;", "R_in=2.9*10**3; #total input resistance from previous question", "A_p=42429.0; #power gain from previous question", "V_CC=15.0;", "I_CC=0.6; #emitter current", "", "#calculation", "P_in=V_in**2/R_in; #input power", "P_out=P_in*A_p;", "P_DC=I_CC*V_CC;", "eff=P_out/P_DC; #efficiency", "", "#result", "print \"efficiency= %.2f\" %eff" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "efficiency= 0.05" ] } ], "prompt_number": 2 }, { "cell_type": "markdown", "source": [ "

Example 9.3, Page Number: 287

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "", "# variable declaration", "V_CC=20.00; #supply voltage", "R_L=16.0; #load resistance", "", "#calculation", "V_out_peak=V_CC; #calculate peak op voltage", "I_out_peak=V_CC/R_L; #calculate peak op current", "", "#result", "print \"ideal maximum peak output voltage = %.2f volts\" %V_out_peak", "print \"ideal maximum current =%.2f amperes\" %I_out_peak" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "ideal maximum peak output voltage = 20.00 volts", "ideal maximum current =1.25 amperes" ] } ], "prompt_number": 3 }, { "cell_type": "markdown", "source": [ "

Example 9.4, Page Number: 288

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "", "# variable declaration", "V_CC=20.0; #supply volatge", "R_L=16.0; #load resistance", "", "#calculation", "V_out_peak=V_CC/2;", "I_out_peak=V_out_peak/R_L;", "", "#result", "print \"ideal maximum output peak voltage = %.2f volts\" %V_out_peak", "print \"ideal maximum current = %.2f amperes\" %I_out_peak" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "ideal maximum output peak voltage = 10.00 volts", "ideal maximum current = 0.62 amperes" ] } ], "prompt_number": 4 }, { "cell_type": "markdown", "source": [ "

Example 9.5, Page Number: 290

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "", "import math", "# variable declaration", "V_CC=20.0; #supply voltage", "R_L=8.0; #load resistance", "B_ac=50.0; #B_ac value", "r_e=6.0; #internal resistance", "", "#calculation", "V_out_peak=V_CC/2;", "V_CEQ=V_out_peak;", "I_out_peak=V_CEQ/R_L;", "I_c_sat=I_out_peak;", "P_out=0.25*I_c_sat*V_CC;", "P_DC=(I_c_sat*V_CC)/math.pi;", "R_in=B_ac*(r_e+R_L);", "", "#result", "print \"maximum ac output power = %.2f Watts\" %P_out", "print \"maximum DC output power = %.2f Watts\" %P_DC", "print \"input resistance = %.2f ohms\" %R_in" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "maximum ac output power = 6.25 Watts", "maximum DC output power = 7.96 Watts", "input resistance = 700.00 ohms" ] } ], "prompt_number": 5 }, { "cell_type": "markdown", "source": [ "

Example 9.6, Page Number: 292

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "", "import math", "# variable declaration", "V_DD=24.0;", "V_in=100*10**-3; #ip volatge", "R1=440.0; #resistance in ohm", "R2=5.1*10**3; #resistance in ohm", "R3=100*10**3; #resistance in ohm", "R4=10**3; #resistance in ohm", "R5=100.0; #resistance in ohm", "R7=15*10**3; #resistance in ohm", "R_L=33.0; #load resistance in ohm", "V_TH_Q1=2.0; # V-TH value", "V_TH_Q2=-2.0; ", "", "#calculation", "I_R1=(V_DD-(-V_DD))/(R1+R2+R3);", "V_B=V_DD-I_R1*(R1+R2); #BASE VOLTAGE", "V_E=V_B+0.7; #EMITTER VOLTAGE", "I_E=(V_DD-V_E)/(R4+R5); #EMITTER CURRENT", "V_R6=V_TH_Q1-V_TH_Q2; #VOLTAGE DROP ACROSS R6", "I_R6=I_E; ", "R6=V_R6/I_R6;", "r_e=25*10**-3/I_E; #UNBYPASSED EMITTER RESISTANCE", "A_v=R7/(R5+r_e); #VOLTAGE GAIN", "V_out=A_v*V_in;", "P_L=V_out**2/R_L;", "", "#result", "print \"value of resistance R6 = %.2d ohms for AB operation\" %R6", "print \"power across load = %.2f watts\"%P_L " ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "value of resistance R6 = 2418 ohms for AB operation", "power across load = 5.15 watts" ] } ], "prompt_number": 6 }, { "cell_type": "markdown", "source": [ "

Example 9.7, Page Number:295

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "", "import math", "# variable declaration", "f=200.0*10**3; #frequency in hertz", "I_c_sat=100.0*10**-3; #saturation current", "V_ce_sat=0.2; #sat voltage", "t_on=1.0*10**-6; #on time", "", "#calculation", "T=1/f; #time period of signal", "P_D_avg=(t_on/T)*I_c_sat*V_ce_sat; #power dissipation", "", "#result", "print \"average power dissipation =%.3f Watts\" %P_D_avg" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "average power dissipation =0.004 Watts" ] } ], "prompt_number": 7 }, { "cell_type": "markdown", "source": [ "

Example 9.8, Page Number: 298

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "", "import math", "# variable declaration", "P_D_avg=4.0*10**-3; #power dissipation", "V_CC=24.0; #supply voltage", "R_c=100.0; #resistance in ohm", "", "#calculation", "P_out=(0.5*V_CC**2)/R_c; #output power", "n=(P_out)/(P_out+P_D_avg); #n is efficiency", "", "#result", "print \"efficiency=%.4f\" %n" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "efficiency=0.9986" ] } ], "prompt_number": 8 } ] } ] }