{
"metadata": {
"name": ""
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 4: Small signal amplifliers"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.1, Page No.118"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# voltage\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Rc=4.7 # in ohm\n",
"Vcc=24.0 # in V\n",
"Ic1=0 # in A\n",
"Ic=1.5 # in mA\n",
"#this is given as 15 mA in textbook which is wrong\n",
"\n",
"#Calculations\n",
"Vce=Vcc-(Ic*Rc*10**-3*10**3)\n",
"Vce1=Vcc-Ic1*Rc\n",
"\n",
"#Result\n",
"print(\"(i) Collector to emitter voltage,Vce(V) = %.2f\"%Vce)\n",
"print(\"(ii) Collector to emitter voltage,Vce(V) = %.f\"%Vce1)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"(i) Collector to emitter voltage,Vce(V) = 16.95\n",
"(ii) Collector to emitter voltage,Vce(V) = 24\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.2, Page No. 118"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# vce\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Beta=100.0\n",
"Rb=200*10**3 # in ohm\n",
"Rc=1*10**3 # in ohm\n",
"Vcc=10.0 # in V\n",
"\n",
"#Calculations\n",
"Ib=Vcc/Rb # in A\n",
"Ic=Beta*Ib # in A\n",
"Vce=Vcc-(Ic*Rc)\n",
"\n",
"#Result\n",
"print(\"Collector to emitter voltage,Vce(V) = %.f\"%Vce)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Collector to emitter voltage,Vce(V) = 5\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.3, Page No. 119"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# base resistance\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Vcc=20.0 # in V\n",
"Vbe=0.73 # in V\n",
"Rc=2.0 # in kilo-ohm\n",
"Icsat= Vcc/Rc #in mA\n",
"Beta=200.0\n",
"\n",
"#RCalculatons\n",
"Ib=(Icsat/Beta)*10**3 # in micro-A\n",
"Rb=((Vcc-Vbe)/(Ib))*10**3 # in kilo-ohm\n",
"\n",
"#Result\n",
"print(\"Rb < %.f kilo-ohm\"%(math.ceil(Rb)))\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Rb < 386 kilo-ohm\n"
]
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.4, Page No. 119"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# operating point\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Vcc=15.0 # in V\n",
"Rb=200.0 # in k-ohm\n",
"Rc=2.0 # in k-ohm\n",
"Beta=50.0\n",
"\n",
"#Calculations\n",
"Ib=(Vcc/(Rb*10**3+(Beta*Rc*10**3)))*10**6\n",
"Ic=Beta*Ib*10**-3\n",
"Vce=Vcc-(Ic*10**-3*(Rc*10**3))\n",
"\n",
"#Result\n",
"print(\"collector current,Ic(mA) = %.1f\"%Ic)\n",
"print(\"Collector to emitter voltage,Vce(V) = %.f\"%Vce)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"collector current,Ic(mA) = 2.5\n",
"Collector to emitter voltage,Vce(V) = 10\n"
]
}
],
"prompt_number": 12
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.5, Page No. 120"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# resistor\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Vcc=15.0 # in V\n",
"Vce=6.0 # in V\n",
"Rc=3*10**3 # in ohm\n",
"Beta=50.0\n",
"\n",
"\n",
"#Calculations\n",
"Ic=(Vcc-Vce)/Rc\n",
"Ib=Ic/Beta;\n",
"Rb=((Vcc/Ib)-(Beta*Rc))*10**-3\n",
"\n",
"#Result\n",
"print(\"The value of resistoe,Rb(k-ohm) = %.f\"%Rb)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The value of resistoe,Rb(k-ohm) = 100\n"
]
}
],
"prompt_number": 14
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.6, Page No. 120"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# operating point\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Vcc=12.0 # in V\n",
"Rb1=70.0 # in k-ohm\n",
"Rb2=70.0 # in k-ohm\n",
"Beta=50.0\n",
"Rc=2.0 # in k-ohm\n",
"\n",
"#Calculations\n",
"Ib=Vcc/((Rb1+Rb2+(Beta*Rc))*10**3)\n",
"Ic=Beta*Ib*10**3\n",
"Vce=Vcc-(Ic*Rc)\n",
"\n",
"#Result\n",
"print(\"Collector current,Ic(mA) = %.1f\"%Ic)\n",
"print(\"Collector to emitter voltage,Vce(V) = %.f\"%Vce)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Collector current,Ic(mA) = 2.5\n",
"Collector to emitter voltage,Vce(V) = 7\n"
]
}
],
"prompt_number": 17
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.7, Page No. 121"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# operating point\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Vcc=9.0 # in V\n",
"Rb=50.0 # in k-ohm\n",
"Rc=250.0 # in ohm\n",
"Re=500.0 # in ohm\n",
"Beta=80.0\n",
"\n",
"#Calculations\n",
"Ib=Vcc/(Rb*10**3+(Beta*Re))\n",
"Ic=Beta*Ib*10**3\n",
"Vce=Vcc-(Ic*10**-3*(Rc+Re));\n",
"\n",
"#Result\n",
"print(\"collector current,Ic(mA) = %.f\"%Ic)\n",
"print(\"Collector to emitter voltage,Vce(V) = %.f\"%Vce)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"collector current,Ic(mA) = 8\n",
"Collector to emitter voltage,Vce(V) = 3\n"
]
}
],
"prompt_number": 19
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.8, Page No. 121"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# operating point\n",
"\n",
"import math\n",
"#Variable declaration\n",
"R2=4.0 # in k-ohm\n",
"R1=40.0 # in k-ohm\n",
"Vcc=22.0 # in V\n",
"Rc=10.0 # in k-ohm\n",
"Re=1.5 # in k-ohm\n",
"Vbe=0.5 # in V\n",
"\n",
"#Calculations\n",
"Voc=R2*10**3*Vcc/((R1+R2)*10**3)\n",
"Ic=(Voc-Vbe)/(Re*10**3)\n",
"Vce=Vcc-(Rc+Re)*Ic*10**3\n",
"\n",
"#Result\n",
"print(\"Collector to emitter voltage,Vce(V) = %.1f\"%Vce)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Collector to emitter voltage,Vce(V) = 10.5\n"
]
}
],
"prompt_number": 21
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.9, Page No.124"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# maximum collector current\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Bv=12.0 # battery voltage in V\n",
"Cl=6.0 # collector load in k-ohm\n",
"\n",
"#Calculations\n",
"CC=Bv/Cl\n",
"\n",
"#Result\n",
"print(\"Collector current,(mA) = %.f\"%CC)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Collector current,(mA) = 2\n"
]
}
],
"prompt_number": 23
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.10, Page No. 125"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# maximum collector current\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Bv=12.0 # battery voltage in V\n",
"P=2.0 # power in Watt\n",
"\n",
"#Calculations\n",
"Ic=(P/Bv)*10**3\n",
"\n",
"#Result\n",
"print(\"The maximum collector current,Ic(mA) = %.1f\"%Ic)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The maximum collector current,Ic(mA) = 166.7\n"
]
}
],
"prompt_number": 25
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.11, Page No. 125"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# gain\n",
"\n",
"import math\n",
"#Variable declaration\n",
"del_ic=1.0 # in mA\n",
"del_ib=10.0 # in micro-A\n",
"del_Vbe=0.02 # in V\n",
"del_ib=10*10**-6 # in A\n",
"Rc=2.0 # in k-ohm\n",
"Rl=10.0 # in k-ohm\n",
"\n",
"#Calculations\n",
"Beta=del_ic/(del_ib*10**3)\n",
"Ri=(del_Vbe/del_ib)*10**-3\n",
"Rac=Rc*Rl/(Rc+Rl);\n",
"Av=round(Beta*Rac/Ri);\n",
"Ap=Beta*Av;\n",
"\n",
"#Result\n",
"print(\"Current gain,Beta = %.f\"%Beta)\n",
"print(\"Input impedence,Ri(k-ohm) = %.f\"%Ri)\n",
"print(\"Effective load,Rac(k-ohm) = %.2f\"%(math.floor(Rac*100)/100))\n",
"print(\"Voltage gain,Av = %.f\"%Av)\n",
"print(\"power gain,Ap = %.f\"%Ap)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Current gain,Beta = 100\n",
"Input impedence,Ri(k-ohm) = 2\n",
"Effective load,Rac(k-ohm) = 1.66\n",
"Voltage gain,Av = 83\n",
"power gain,Ap = 8300\n"
]
}
],
"prompt_number": 70
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.12, Page No. 125"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# output voltage\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Rc=10.0 # in k-ohm\n",
"Rl=10 # in k-ohm\n",
"Beta=100.0\n",
"Ri=2.5\n",
"Iv=2.0 # input voltage in mV\n",
"\n",
"#Calculations\n",
"Rac=Rc*Rl/(Rc+Rl)\n",
"Av=round(Beta*Rac/Ri)\n",
"Ov=Av*Iv*10**-3\n",
"\n",
"#Result\n",
"print(\"Output voltage,(V) = %.1f\"%Ov)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Output voltage,(V) = 0.4\n"
]
}
],
"prompt_number": 34
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.13, Page No.133"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# gain and resistance \n",
"\n",
"import math\n",
"#Variable declaration\n",
"I=1.0\n",
"hfe=46.0\n",
"hoe=80*10**-6\n",
"hre=5.4*10**-4\n",
"hie=800.0 # in ohm\n",
"RL=5*10**3 # in ohm\n",
"Rg=500 # in ohm\n",
"\n",
"#Result\n",
"Aie=hfe/(I+(hoe*RL))\n",
"Aie = math.floor(Aie*10)/10\n",
"Zie=hie-(hre*RL*Aie)\n",
"Ave=(Aie*RL)/Zie\n",
"Ave=math.floor(Ave*10)/10\n",
"Zoe=((hie+Rg)/(hoe*(hie+Rg)-(hfe*hre)))/10**3\n",
"Ape=Aie*Ave\n",
"\n",
"#Result\n",
"print(\"Current gain,Aie = %.1f\"%(Aie))\n",
"print(\"Input resistance,Zie(ohm) = %.1f\"%(Zie))\n",
"print(\"Voltage gain,Ave = %.1f\"%Ave)\n",
"print(\"Output resistance,Zoe(k-ohm) = %.1f\"%Zoe)\n",
"print(\"Power gain,Ape = %.1f\"%Ape)\n",
"#voltage gain and power gain are calculated wrong in the textbook"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Current gain,Aie = 32.8\n",
"Input resistance,Zie(ohm) = 711.4\n",
"Voltage gain,Ave = 230.5\n",
"Output resistance,Zoe(k-ohm) = 16.4\n",
"Power gain,Ape = 7560.4\n"
]
}
],
"prompt_number": 79
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.14, Page No.141"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# gain and voltage\n",
"\n",
"import math\n",
"#Variable declaration\n",
"A=100.0 # gain without feedback\n",
"Beta=1.0/25 # feed back ratio\n",
"vi=50.0 # mV\n",
"Af=(A/(1+(Beta*A))) # gain with feedback\n",
"ff=Beta*A # feedback factor\n",
"Vo=Af*vi*10**-3 # in V\n",
"fv=Beta*Vo # in V\n",
"vin=vi*(1+Beta*A) # mV\n",
"\n",
"#Result\n",
"print(\"gain with feedback is , = %.f\"%Af)\n",
"print(\"feedback factor is, = %.f\"%ff)\n",
"print(\"output voltage is ,(V) = %.f\"%Vo)\n",
"print(\"feedback voltage is ,(V) = %.2f\"%fv)\n",
"print(\"new increased input voltage is ,(mV) = %.f\"%vin)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"gain with feedback is , = 20\n",
"feedback factor is, = 4\n",
"output voltage is ,(V) = 1\n",
"feedback voltage is ,(V) = 0.04\n",
"new increased input voltage is ,(mV) = 250\n"
]
}
],
"prompt_number": 40
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.15, Page No. 142"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# voltage gain\n",
"\n",
"import math\n",
"#Variable declaration\n",
"A=1000.0 # gain without feedback\n",
"fctr=0.40 # gain reduction factor\n",
"\n",
"A2=800.0 # redued gain\n",
"\n",
"#Calculations\n",
"Af=A-fctr*A # gain with feedback\n",
"Beta=((A/Af)-1)/A # feed back ratio\n",
"Af2=((A2)/(1+(Beta*A2)))\n",
"prfb= ((A-A2)/A)*100 #percentage reduction without feedback\n",
"prwfb= ((Af-Af2)/Af)*100 #percentage reduction without feedback\n",
"\n",
"#Result\n",
"print(\"(i) voltage gain is , = %.1f\"%Af2)\n",
"print(\"(ii) percentage reduction without feedback is,(%%) = %.f\"%prfb)\n",
"print(\" percentage reduction with feedback is,(%%) = %.2f\"%(math.ceil(prwfb*100)/100))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"(i) voltage gain is , = 521.7\n",
"(ii) percentage reduction without feedback is,(%) = 20\n",
" percentage reduction with feedback is,(%) = 13.05\n"
]
}
],
"prompt_number": 81
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.16, Page No. 142"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# small change in gain\n",
"\n",
"import math\n",
"#Variable declaration\n",
"A=200.0 #gain without feedback\n",
"Beta=0.25 #feed back ratio\n",
"gc=10 #percent gain change\n",
"\n",
"#Calculations\n",
"dA=gc/100.0\n",
"dAf= ((1/(1+Beta*A)))*dA\n",
"#Result\n",
"print(\"small change in gain is, = %.4f\"%(math.floor(dAf*10**4)/10**4))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"small change in gain is, = 0.0019\n"
]
}
],
"prompt_number": 58
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.17, Page No.143"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# input voltage\n",
"\n",
"import math\n",
"#Variable declaration\n",
"A=200.0 # gain without feedback\n",
"Beta=0.05 # feed back ratio\n",
"Dn=10.0 # percentage distortion\n",
"vo=0.5 # initial output voltage\n",
"\n",
"#Calculations\n",
"Af=(A/(1+(Beta*A))) # gain with feedback\n",
"Dn1=(Dn/(1+A*Beta)) # percentage Distortion with negative feedback\n",
"ff=Beta*A # feedback factor\n",
"vi=A*vo # in V\n",
"vin=vi/Af # in V\n",
"\n",
"#Result\n",
"print(\"gain with negative feedback is , = %.1f\"%Af)\n",
"print(\"percentage Distortion with negative feedback is ,(%%) = %.3f\"%Dn1)\n",
"print(\"new input voltage is ,(V) = %.1f\"%vin)\n",
"#gain and input voltage are calculated wrong in the textbook "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"gain with negative feedback is , = 18.2\n",
"percentage Distortion with negative feedback is ,(%) = 0.909\n",
"new input voltage is ,(V) = 5.5\n"
]
}
],
"prompt_number": 83
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.18, Page No. 143"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# percentage of feedback\n",
"\n",
"import math\n",
"#Variable declaration\n",
"A=50.0 # gain without feedback\n",
"Af=10.0 # gain with feedback\n",
"\n",
"#Calculations\n",
"Beta=(((A/Af)-1)/A)*100 # feed back ratio\n",
"print(\"percentage of feedback is ,(%%) = %.f\"%Beta)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"percentage of feedback is ,(%) = 8\n"
]
}
],
"prompt_number": 84
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.19, Page No. 144"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# band width\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Bw=200.0 # bandwidth in kHz\n",
"vg=40.0 # dB\n",
"fb=5.0 # percentage negetive feedback\n",
"A=40.0 # gain without feedback\n",
"\n",
"#Calculations\n",
"Beta=fb/100 # feed back ratio\n",
"Af=(A/(1+(Beta*A))) # gain with feedback\n",
"Bwf= (A*Bw)/Af # Bandwidth with feedback\n",
"\n",
"#Result\n",
"print(\" new band-width is ,(kHz) = %.f\"%Bwf)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" new band-width is ,(kHz) = 600\n"
]
}
],
"prompt_number": 52
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.20, Page No. 144"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# percentage reduction\n",
"\n",
"import math\n",
"#Variable declaration\n",
"A=50.0 # gain without feedback\n",
"Af=25.0 # gain with feedback\n",
"Ad=40.0 # new gain after ageing\n",
"\n",
"#Calculations\n",
"Beta=(((A/Af)-1)/A) # feed back ratio\n",
"Af1=(Ad/(1+(Beta*Ad)))# new gain with feedback\n",
"df=Af-Af1 # reduction in gain\n",
"pdf= (df/Af)*100 # percentage reduction in gain\n",
"\n",
"#Result\n",
"print(\" percentage reduction in gain is ,(%%) = %.1f\"%pdf)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" percentage reduction in gain is ,(%) = 11.1\n"
]
}
],
"prompt_number": 55
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.21, Page No. 145"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Av and beta\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Af=100.0 # gain with feeback\n",
"vi=50.0 # in mV\n",
"vi1=60.0 # in mV\n",
"\n",
"#Calcualtion\n",
"AAf=vi1/vi\n",
"A=AAf*Af\n",
"Beta=(((A/Af)-1)/A)\n",
"\n",
"#Result\n",
"print(\"Av is ,= %.f\"%A)\n",
"print(\"feedback factor is, = %.5f or 1/600\"%Beta)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Av is ,= 120\n",
"feedback factor is, = 0.00167 or 1/600\n"
]
}
],
"prompt_number": 57
}
],
"metadata": {}
}
]
}