{
"metadata": {
"name": ""
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 15 : Operational Amplifier"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 15.1a, Page No 572"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#initialisation of variables\n",
"v11=50.0 #in microV\n",
"v21=-50.0 #in microV\n",
"#Second Set of Input Signal\n",
"v12=1050.0 #in microV\n",
"v22=950.0 #in microV\n",
"p=100.0 #Common Mode Rejection Ratio\n",
"\n",
"#Required Formulae\n",
"#vo = Ad*vd*(1+vc/p*vd) .... p = commom mode rejection ratio\n",
"#Ad will be same for both case, So let us write Vo = vo/Ad = Ad*(1+vc/p*vd)\n",
"\n",
"#Calculations\n",
"#First Set of Values\n",
"vd1=v11-v21#in microV\n",
"vc1=(v11+v21)/2#in microV\n",
"Vo1 = vd1*(1+vc1/(p*vd1))\n",
"\n",
"#Second Set of Values\n",
"vd2=v12-v22#in microV\n",
"vc2=(v12+v22)/2#in microV\n",
"Vo2 = vd2*(1+vc2/(p*vd2))\n",
"\n",
"#Results\n",
"print(\"Percentage difference in output signal = %.2f v \" %(100*(Vo2-Vo1)/Vo1))\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Percentage difference in output signal = 10.00 v \n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 15.1b, Page No 572"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"\n",
"#initialisation of variables\n",
"v11=50.0 #in microV\n",
"v21=-50.0 #in microV\n",
"#Second Set of Input Signal\n",
"v12=1050.0 #in microV\n",
"v22=950.0 #in microV\n",
"p=100.0 #Common Mode Rejection Ratio\n",
"\n",
"#Required Formulae\n",
"#vo = Ad*vd*(1+vc/p*vd) .... p = commom mode rejection ratio\n",
"#Ad will be same for both case, So let us write Vo = vo/Ad = Ad*(1+vc/p*vd)\n",
"\n",
"#Calculations\n",
"#First Set of Values\n",
"vd1=v11-v21#in microV\n",
"vc1=(v11+v21)/2#in microV\n",
"Vo1 = vd1*(1+vc1/(p*vd1))\n",
"\n",
"#Second Set of Values\n",
"vd2=v12-v22#in microV\n",
"vc2=(v12+v22)/2#in microV\n",
"Vo2 = vd2*(1+vc2/(p*vd2))\n",
"\n",
"\n",
"#Now we have to calculate the same thing with common mode rejection ratio = 10000\n",
"\n",
"p=10000#Common Mode Rejection Ratio\n",
"\n",
"#First Set of Values\n",
"vd1=v11-v21#in microV\n",
"vc1=(v11+v21)/2#in microV\n",
"Vo1 = vd1*(1+vc1/(p*vd1))\n",
"\n",
"#Second Set of Values\n",
"vd2=v12-v22#in microV\n",
"vc2=(v12+v22)/2#in microV\n",
"Vo2 = vd2*(1+vc2/(p*vd2))\n",
"\n",
"#Results\n",
"print(\"Percentage difference in output signal = %.2f v \" %(100*(Vo2-Vo1)/Vo1))\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Percentage difference in output signal = 0.10 v \n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 15.2 Page No 576"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"\n",
"#initialisation of variables\n",
"Vbe1=0.7\n",
"Vce3=0.2\n",
"I3=5.0\n",
"R3=0.4\n",
"Vee=5\n",
"Vcc=5\n",
"Ic1=2.5\n",
"Rc=1.0\n",
"\n",
"#Calculations\n",
"Vcmmin=Vbe1+Vce3+(I3*R3)-Vee\n",
"Vcmmax=Vcc-(Ic1*Rc)+0.6\n",
"\n",
"#Results\n",
"print(\"The Vcm can vary from = %.2f v to \" %Vcmmin)\n",
"print(\"%.2f v \" %Vcmmax)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The Vcm can vary from = -2.10 v to \n",
"3.10 v \n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 15.3 Page No 583"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"\n",
"#initialisation of variables\n",
"Vbe2=0.7\n",
"Vce1=0.2\n",
"I1=0.99\n",
"R1=2.2\n",
"Vee=6\n",
"Vcc=6\n",
"Ic2=0.495\n",
"R2=7.75\n",
"Vbc2=0.6\n",
"\n",
"#Calculations\n",
"Vcmmin=Vbe2+Vce1+(I1*R1)-Vee\n",
"Vcmmax=Vcc-(Ic2*R2)+0.6\n",
"\n",
"#Results\n",
"print(\"The Vcm can vary from = %.2f v to \" %Vcmmin)\n",
"print(\"%.2f v \" %Vcmmax)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The Vcm can vary from = -2.92 v to \n",
"2.76 v \n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 15.4 Page No 596"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"\n",
"#initialisation of variables\n",
"\n",
"f=32.0 #feedback in dB\n",
"#from the Bodes plot we get that Avo = 2510\n",
"Avo = 2510.0 #gain\n",
"print('The parameters are R , r (for Rdash), C (for Cdash)')\n",
"#Desensivity D = B*Rmo = Avo*(R/(R+r))\n",
"#20log10(D ) = f\n",
"\n",
"#Calculations\n",
"k = f - (20*math.log(Avo,10))\n",
"#Let (R+r)/R = l\n",
"l = 1.0/(10**(k/20))\n",
"#R/(R+r) = fp/fz\n",
"#For 45degree phase margin and 32dB of low frequency feedback we find by trial and error method from the graph\n",
"fz = 10#in MHz\n",
"fp = fz*l\n",
"#to determine c we can arbitrarily choose R\n",
"R = 1000.0 #in ohm\n",
"\n",
"#Results\n",
"print(\"R = %.2f ohm \" %R)\n",
"r = (l-1)*R\n",
"print(\"r = %.2f ohm \" %r)\n",
"C = 1/(2*math.pi*fz*r*10**-6)\n",
"print(\"C = %.2f pF \" %C)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The parameters are R , r (for Rdash), C (for Cdash)\n",
"R = 1000.00 ohm \n",
"r = 62048.35 ohm \n",
"C = 0.26 pF \n"
]
}
],
"prompt_number": 5
}
],
"metadata": {}
}
]
}