{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter-4 : Frequency Response Of An Op-Amp" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example : 4.1 - Page No 134" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "# Given data\n", "Vin= 0.5 # in V\n", "Av= 10 \n", "I_B_max= 1.5 # in micro amp\n", "I_B_max=I_B_max*10**-6 # in A\n", "# Let\n", "I1=100*I_B_max # in A\n", "R1= Vin/I1 # in ohm\n", "Rf= Av*R1 # in ohm\n", "# R2= R1 || Rf = R1 (approx.)\n", "R2= R1 # in ohm\n", "print \"Value of I1 = %0.f micro amp\" %(I1*10**6)\n", "print \"Value of R1 = %0.1f kohm\" %(R1*10**-3)\n", "print \"Value of R2 = %0.1f kohm\" %(R2*10**-3)\n", "print \"Value of Rf = %0.f kohm\" %(Rf*10**-3)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Value of I1 = 150 micro amp\n", "Value of R1 = 3.3 kohm\n", "Value of R2 = 3.3 kohm\n", "Value of Rf = 33 kohm\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example : 4.2 - Page No 134" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import log10\n", "# Given data\n", "Vin= 50 # in mV\n", "Vin = Vin*10**-3 # in V\n", "I_B_max= 200 # in nA\n", "I_B_max=I_B_max*10**-9 # in A\n", "I1=100*I_B_max # in A(assumed)\n", "Av=100 \n", "R1= Vin/I1 # in \u03a9\n", "print \"The value of R1 = %0.1f k\u03a9 (Standard value 2.2 k\u03a9)\" %(R1*10**-3)\n", "R1= 2.2 # kohm (standard value)\n", "Rf= Av*R1 # in kohm\n", "print \"The value of Rf = %0.f k\u03a9\" %Rf\n", "# R2 = R1 || Rf = R1 (approx)\n", "R2= R1 # in kohm\n", "print \"The value of R2 = %0.1f k\u03a9\" %R2\n", "Av= 20*log10(Av) # in dB\n", "C1= 100 # in pF\n", "R1= 1.5 # in k\u03a9\n", "C2= 3 # in pF\n", "print \"Voltage gain = %0.f dB\" %Av\n", "print \"Value of C1 = %0.f pF\" %C1\n", "print \"Value of C2 = %0.f pF\" %C2\n", "print \"Value of R1 = %0.1f k\u03a9\" %R1" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The value of R1 = 2.5 k\u03a9 (Standard value 2.2 k\u03a9)\n", "The value of Rf = 220 k\u03a9\n", "The value of R2 = 2.2 k\u03a9\n", "Voltage gain = 40 dB\n", "Value of C1 = 100 pF\n", "Value of C2 = 3 pF\n", "Value of R1 = 1.5 k\u03a9\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example : 4.3 - Page No 136\n", " " ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Given data\n", "A_VD= 200 # in V/mV\n", "A_VD=A_VD*10**3 # in V/V\n", "B1=1 # in MHz\n", "B1=B1*10**6 # in Hz\n", "f1=B1 \n", "f0= f1/A_VD # in Hz\n", "print \"Cut-off frequency = %0.f Hz\" %f0" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Cut-off frequency = 5 Hz\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example : 4.4 - Page No 143\n", " " ] }, { "cell_type": "code", "collapsed": false, "input": [ "from numpy import pi\n", "# Given data\n", "Vin= 15 # in volt\n", "SR= 0.8 # in V/micro sec\n", "SR=SR*10**6 # in V/sec\n", "omega= SR/Vin \n", "f= omega/(2*pi) # in Hz\n", "print \"Full power bandwidth = %0.1f kHz\" %(f*10**-3)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Full power bandwidth = 8.5 kHz\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example : 4.5 - Page No 143\n", " " ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Given data\n", "SR= 2 # in V/micro sec\n", "del_v_in= 0.5 # in volt\n", "del_t=10 #in micro sec\n", "del_v_inBYdel_t= del_v_in/del_t # in V/micro sec\n", "# v_out= A_CL*v_in\n", "A_CL= SR/del_v_inBYdel_t \n", "print \"Closed-loop gain = %0.f \" %A_CL" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Closed-loop gain = 40 \n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example : 4.6 - Page No 144" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Given data\n", "Vpp= 3 # in volts\n", "del_V= Vpp*(90-10)/100 # in volts\n", "del_t= 4 # in micro sec\n", "SR_required= del_V/del_t # in V/micro sec\n", "print \"The required SR = %0.1f V/micro sec\" %SR_required\n", "print \"(i) The 741 op-amp has an SR of 0.5 volts per micro second. It is too slow so it cannot be used\"\n", "print \"(ii) The 318 op-amp has an SR of 50 volts per micro second. It is fast enough and can be used.\"\n", "SR= 50 # V/micro sec\n", "# Rise time using a 318 op-amp,\n", "del_t= del_V/SR # in micro sec \n", "del_t= del_t*10**3 # in ns\n", "print \" The reise time using 318 op-amp = %0.f ns\" %del_t\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The required SR = 0.6 V/micro sec\n", "(i) The 741 op-amp has an SR of 0.5 volts per micro second. It is too slow so it cannot be used\n", "(ii) The 318 op-amp has an SR of 50 volts per micro second. It is fast enough and can be used.\n", " The reise time using 318 op-amp = 48 ns\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example : 4.7 - Page No 144" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "from numpy import pi\n", "# Given data\n", "Vout= 6 # in volts\n", "Vin= 20*10**-3 # in V\n", "Vrms= 1.414\n", "Vout_peak= 6*Vrms # in volts\n", "f_max= 15 # in kHz\n", "# Required closed loop gain\n", "A_CL= Vout/Vin \n", "# Required SR\n", "SRmax= 2*pi*Vout_peak*f_max # in V/micro sec\n", "print \"(i) The 741 has an SR of 0.5 V/micro sec. It is too slow and would distort the sine wave output.\"\n", "print \"(ii) The 318 has an SR of 50 V/micro sec. It is fast enough to develop a 6 Vrms sine wave output at 15 kHz.\"\n", "f_1per= 15 # kHz\n", "# The gain bandwidth,\n", "GBW= 7*A_CL*f_1per # in kHz\n", "GBW= GBW*10**-3 # in MHz\n", "print \" The gain bandwidth = %0.1f MHz\" %GBW\n", "print \" The GBW for 318 op-amp is only 15 MHz. So even though the 318 op-amp satisfies the SR requirement but\"\n", "print \" it does not have a large enough GBW to proved a gain of 300 (\u00b11 %) at 15 kHz\"\n", "\n", "A_CL= 10\n", "GBW10= 7*A_CL*f_1per # in kHz\n", "GBW10= GBW10*10**-3 # in MHz\n", "print \"GBW (Gain of 10) = %0.2f MHz\" %GBW10\n", "A_CL= 30\n", "GBW30= 7*A_CL*f_1per # in kHz\n", "GBW30= GBW30*10**-3 # in MHz\n", "print \"GBW (Gain of 30) = %0.2f MHz\" %GBW30\n", "print \"The 318 op-amp has a large enough gain bandwidth to operate both amplifiers.\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(i) The 741 has an SR of 0.5 V/micro sec. It is too slow and would distort the sine wave output.\n", "(ii) The 318 has an SR of 50 V/micro sec. It is fast enough to develop a 6 Vrms sine wave output at 15 kHz.\n", " The gain bandwidth = 31.5 MHz\n", " The GBW for 318 op-amp is only 15 MHz. So even though the 318 op-amp satisfies the SR requirement but\n", " it does not have a large enough GBW to proved a gain of 300 (\u00b11 %) at 15 kHz\n", "GBW (Gain of 10) = 1.05 MHz\n", "GBW (Gain of 30) = 3.15 MHz\n", "The 318 op-amp has a large enough gain bandwidth to operate both amplifiers.\n" ] } ], "prompt_number": 30 } ], "metadata": {} } ] }