{
"metadata": {
"name": ""
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 3 : Op-amp with Negative Feedback"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"example 3.1, Page No. 90"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# parameters of practical invertig amplifier\n",
"\n",
"import math\n",
"#VAriable declaration\n",
"R1 = 470 # Resistor R1\n",
"Rf = 4.7*10**3 # feedback resistor\n",
"A = 2*10**5 # Open loop gain\n",
"Rin= 2*10**6 # input resistance\n",
"Ro = 75 # output resistance\n",
"f = 5 # single break frequency\n",
"V = 15 # dual supply voltage\n",
"\n",
"#Calculations\n",
"K = Rf/(R1+Rf)\n",
"B = R1/(R1+Rf)\n",
"B = math.floor(B*10000)/10000 \n",
"Af = (-A*Rf)/(R1+Rf+R1*A)\n",
"Rinf = R1+(Rf*Rin/(Rf+Rin+A*Rin))\n",
"Rof = Ro/(1+A*B)\n",
"ff = f*(1+A*B)\n",
"\n",
"#Result\n",
"print(\"Closed loop voltage gain with feedback = %.0f\\nInput resistane with feedback = %.4f ohm\"%(math.floor(Af),Rinf))\n",
"print(\"Output resistance with feedback = %.2f m-ohm\\nBandwidth with feedback = %.3f KHz\"%(Rof*1000,ff/1000))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Closed loop voltage gain with feedback = -10\n",
"Input resistane with feedback = 470.0235 ohm\n",
"Output resistance with feedback = 4.13 m-ohm\n",
"Bandwidth with feedback = 90.905 KHz\n"
]
}
],
"prompt_number": 47
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"example 3.2, Page No. 91"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# inverting Op-amp design\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Af = -30.0 # voltage gain\n",
"Rf = 1*10**6 # feedback resistance\n",
"\n",
"#Calcaculation\n",
"R1 = -Rf/Af\n",
"\n",
"#Result\n",
"print(\"R1 = %.2f k-ohm\\nlet us choose, R1 = 30 k-ohm + 3.3 k-ohm......standard values(refer fig. 3.7)\"%(R1/1000))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"R1 = 33.33 k-ohm\n",
"let us choose, R1 = 30 k-ohm + 3.3 k-ohm......standard values(refer fig. 3.7)\n"
]
}
],
"prompt_number": 24
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"example 3.3, Page No. 91"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print(\"Theoretical example\")"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Theoretical example\n"
]
}
],
"prompt_number": 25
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"example 3.4, Page No. 95"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Value of feedback resistance\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Af = 61 # gain with feedback\n",
"R1 = 1000 # resistor R1\n",
"\n",
"\n",
"#Calculations\n",
"Rf = (Af-1)*R1\n",
"\n",
"#Result\n",
"print(\"Rf = %d k-ohm\"%(Rf/1000))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Rf = 60 k-ohm\n"
]
}
],
"prompt_number": 29
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"example 3.5, Page No.95"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# parameters of non-invertig amplifier\n",
"\n",
"import math\n",
"#VAriable declaration\n",
"R1 = 1000.0 # Resistor R1\n",
"Rf = 10*10**3 # feedback resistor\n",
"A = 2*10**5 # Open loop gain\n",
"Rin= 2*10**6 # input resistance\n",
"Ro = 75 # output resistance\n",
"f = 5 # single break frequency\n",
"V = 12 # dual supply voltage\n",
"\n",
"#Calculations\n",
"B = R1/(R1+Rf)\n",
"#B = math.floor(B*10000)/10000 \n",
"Af = A/(1+A*B)\n",
"Rinf = Rin*(1+A*B)\n",
"Rof = Ro/(1+A*B)\n",
"ff = f*(1+A*B)\n",
"\n",
"#Result\n",
"print(\"Closed loop voltage gain with feedback = %.3f\\nInput resistane with feedback = %.2f G-ohm\"%(Af,math.floor((Rinf/10**9)*100)/100))\n",
"print(\"Output resistance with feedback = %.2f m-ohm\\nBandwidth with feedback = %.2f KHz\"%(Rof*1000,ff/1000))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Closed loop voltage gain with feedback = 10.999\n",
"Input resistane with feedback = 36.36 G-ohm\n",
"Output resistance with feedback = 4.12 m-ohm\n",
"Bandwidth with feedback = 90.91 KHz\n"
]
}
],
"prompt_number": 48
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"example 3.6, Page No. 96"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# inverter parameters\n",
"\n",
"import math\n",
"#Variable declaration\n",
"A = 2*10**5 # Open loop gain\n",
"Rin= 2*10**6 # input resistance\n",
"Ro = 75 # output resistance\n",
"f = 5 # single break frequency\n",
"\n",
"\n",
"#Calculations\n",
"Af = -1 # inverter gain\n",
"Rf = 330.0 # Rf = R1, Value assumed\n",
"R1 = Rf\n",
"B = R1/(R1+Rf)\n",
"Rof = Ro/(A*B)\n",
"BW = f*(A*B)\n",
"\n",
"#Result\n",
"print(\"Af = %.0f\\nRif = %.0f ohm\\nRof = %.5f ohm\\nfF = %.1f MHz\"%(Af,Rf,Rof,BW/10**6))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Af = -1\n",
"Rif = 330 ohm\n",
"Rof = 0.00075 ohm\n",
"fF = 0.5 MHz\n"
]
}
],
"prompt_number": 42
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"example 3.7, Page No. 96"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# parameters of invertig and non-inverting amplifier\n",
"\n",
"import math\n",
"#VAriable declaration\n",
"R1_n = 1000.0 # Resistor R1 in case of non-inverting ampliflier\n",
"Rf_n = 10*10**3 # feedback resistor in case of non-inverting ampliflier\n",
"R1_i = 470.0 # Resistor R1 in case of inverting ampliflier\n",
"Rf_i = 4.7*10**3 # feedback resistor in case of inverting ampliflier\n",
"A = 2*10**5 # Open loop gain\n",
"Ri = 2*10**6 # input resistance\n",
"Ro = 75 # output resistance\n",
"f = 5 # single break frequency\n",
"V = 15 # dual supply voltage\n",
"Vos = 13 # output voltage swing\n",
"\n",
"#Calculations\n",
"#(i) Non-inverting amplifier\n",
"B = R1_n/(R1_n+Rf)\n",
"Af = 1+(Rf_n/R1_n)\n",
"Rinf = Ri*(1+A*B)\n",
"Rof = Ro/(1+A*B)\n",
"ff = f*(1+A*B)\n",
"ff =ff/1000 # KHz\n",
"VooT = Vos/(1+A*B)\n",
"#(ii) Inverting amplifier\n",
"B_i = R1_i/(R1_i+Rf)\n",
"Af_i = -(Rf_i/R1_i)\n",
"Rinf_i = R1_i\n",
"Rof_i = Ro/(1+A*B_i)\n",
"ff_i = f*(1+A*B_i)\n",
"ff_i =ff_i/1000 # KHz\n",
"VooT_i = Vos/(1+A*B_i)\n",
"\n",
"#Result\n",
"print(\"(i) Non-inverting amplifier:\")\n",
"print(\" Closed loop voltage gain with feedback = %.0f\\n Input resistane with feedback = %.4f ohm\"%(math.floor(Af),Rinf/10**9))\n",
"print(\" Output resistance with feedback = %.5f ohm\\n Bandwidth with feedback = %.2f KHz\"%(Rof,math.ceil(ff*100)/100))\n",
"print(\" Total output offset voltage with feedback = +/- %.3f mV\"%(VooT*1000))\n",
"\n",
"print(\"\\n(ii) Inverting amplifier:\")\n",
"print(\" Closed loop voltage gain with feedback = %.0f\\n Input resistane with feedback = %.0f ohm\"%(math.floor(Af_i),Rinf_i))\n",
"print(\" Output resistance with feedback = %.5f ohm\\n Bandwidth with feedback = %.2f KHz\"%(Rof,math.ceil(ff*100)/100))\n",
"print(\" Total output offset voltage with feedback = +/- %.3f mV\"%(VooT*1000))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"(i) Non-inverting amplifier:\n",
" Closed loop voltage gain with feedback = 11\n",
" Input resistane with feedback = 36.3656 ohm\n",
" Output resistance with feedback = 0.00412 ohm\n",
" Bandwidth with feedback = 90.92 KHz\n",
" Total output offset voltage with feedback = +/- 0.715 mV\n",
"\n",
"(ii) Inverting amplifier:\n",
" Closed loop voltage gain with feedback = -10\n",
" Input resistane with feedback = 470 ohm\n",
" Output resistance with feedback = 0.00412 ohm\n",
" Bandwidth with feedback = 90.92 KHz\n",
" Total output offset voltage with feedback = +/- 0.715 mV\n"
]
}
],
"prompt_number": 68
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"example 3.8, Page No. 97"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# inverting amplifier parameters\n",
"\n",
"import math\n",
"#variable declaration\n",
"Rf = 500*10**3 # feedback resistance\n",
"R1 = 5*10**3 # R1 resistance\n",
"Vi = 0.1 # input voltage\n",
"\n",
"\n",
"#Calculation\n",
"Af = -Rf/R1\n",
"Ri = R1\n",
"Ro = 0\n",
"Vout = Af*Vi\n",
"Iin = Vi/R1\n",
"\n",
"#Result\n",
"print(\"Af = %d\\nRi = %d k-ohm\\nRo = %d ohm\\nVout = %d V\\nIin = %.2f mA\"%(Af,Ri/1000,Ro,Vout,Iin*1000))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Af = -100\n",
"Ri = 5 k-ohm\n",
"Ro = 0 ohm\n",
"Vout = -10 V\n",
"Iin = 0.02 mA\n"
]
}
],
"prompt_number": 76
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"example 3.9, Page No.97"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# input ippedance, Voltage gain and power gain(refer fig. 3.15)\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Rf = 1*10**6 # feedback resistance\n",
"Rin = 1*10**6 # input resistance\n",
"\n",
"#Calculations\n",
"Av = -Rf/Rin\n",
"Ai = 1 #unity gain inverter\n",
"Ap = abs(Av*Ai)\n",
"\n",
"#Result\n",
"print(\"(i) Given amplifier is an inverting amplifier,therefore, Av = %.0f\"%Av)\n",
"print(\"(ii) Because it is a unity gain inverter, so Ai = %.0f\"%Ai)\n",
"print(\"(iii) Power gain of op-amp circuit, Ap = %.0f\"%Ap)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"(i) Given amplifier is an inverting amplifier,therefore, Av = -1\n",
"(ii) Because it is a unity gain inverter, so Ai = 1\n",
"(iii) Power gain of op-amp circuit, Ap = 1\n"
]
}
],
"prompt_number": 79
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"example 3.10, Page No. 98"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# inverting op-amp circuit design\n",
"\n",
"import math\n",
"# Variable declaartion\n",
"Av = -8 # voltage gain\n",
"Vin = -1 # input voltage\n",
"I1 = 15*10**-6 # maximum current through R1 and Rf\n",
"\n",
"#Calculations\n",
"R1 = abs(Vin)/I1\n",
"R1std = 68*10**3 # standard value\n",
"Rf = -Av*R1\n",
"\n",
"#Result\n",
"print(\"R1 = %.2f K-ohm\\t\\t(we use %.0f K-ohm as standard value)\"%(R1/1000,R1std/1000))\n",
"print(\"Rf = %f K-ohm\"%(Rf/1000))\n",
"#Answer for Rf is wrong in the book"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"R1 = 66.67 K-ohm\t\t(we use 68 K-ohm as standard value)\n",
"Rf = 533.333333 K-ohm\n"
]
}
],
"prompt_number": 85
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"example 3.11, Page No. 98"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print(\"Theoretical example\")"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Theoretical example\n"
]
}
],
"prompt_number": 86
}
],
"metadata": {}
}
]
}