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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"CHAPTER 19 NEGATIVE FEEDBACK"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-1, Page 709"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"Vin=50 #input voltage(mV)\n",
"Rf=3.9 #feedback path resistance Rf (KOhm)\n",
"R1=0.1 #inverting input resistance R1(KOhm)\n",
"AVOL=100000 #open loop voltage gain\n",
"\n",
"B=R1/(Rf+R1) #feedback fraction\n",
"Av=B**-1 #closed loop voltage gain\n",
"Err=100/(1+AVOL*B) #percent error (%)\n",
"Av1=Av-((Av/100)*Err) #closed loop voltage gain1\n",
"Av2=AVOL/(1+AVOL*B) #closed loop voltage gain2\n",
"\n",
"print 'closed loop voltage gain by approach 1 = ',round(Av1,2)\n",
"print 'closed loop voltage gain by approach 2 = ',round(Av2,2)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"closed loop voltage gain by approach 1 = 39.98\n",
"closed loop voltage gain by approach 2 = 39.98\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-2, Page 713"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"Vin=50 #input voltage(mV)\n",
"Rf=3.9*10**3 #feedback path resistance Rf (Ohm)\n",
"R1=100 #inverting input resistance R1(Ohm)\n",
"AVOL=100000 #open loop voltage gain\n",
"B=0.025 #feedback fraction\n",
"Rin=2*10**6 #open loop input resistance(Ohm)\n",
"RCM=200*10**6 #common mode input resistance(Ohm)\n",
"\n",
"Zin_CL=(1+(AVOL*B))*Rin #closed loop input impedance(Ohm)\n",
"Zin_CL1=RCM*Zin_CL/(RCM+Zin_CL) #closed loop input impedance(Ohm)\n",
"\n",
"print 'closed loop input impedance Zin(CL) = ',round((Zin_CL1/10**6),2),'MOhm'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"closed loop input impedance Zin(CL) = 192.31 MOhm\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-3, Page 714"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"Rout=75 #open loop output resistance(Ohm)\n",
"AVOL=100000 #open loop voltage gain\n",
"B=0.025 #feedback fraction\n",
"\n",
"Zout_CL=Rout/(1+AVOL*B) #closed loop input impedance(Ohm)\n",
"\n",
"print 'closed loop output impedance Zout(CL) = ',round(Zout_CL,2),'Ohm'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"closed loop output impedance Zout(CL) = 0.03 Ohm\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-4, Page 714"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"THD=7.5 #open loop total harmonic distortion (%)\n",
"AVOL=100000 #open loop voltage gain\n",
"B=0.025 #feedback fraction\n",
"\n",
"THD_CL=THD/(1+AVOL*B) #closed loop total harmonic distortion (%)\n",
"\n",
"print 'Closed loop total harmonic distortion THD(CL) = ',round(THD_CL,3),'%'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Closed loop total harmonic distortion THD(CL) = 0.003 %\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-5, Page 716"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"Iin=1 #input current(mA)\n",
"Rf=5 #feedback path resistance Rf (KOhm)\n",
"\n",
"Vout=-(Iin*Rf) #Output voltage at 1KHz (Vpp) \n",
"\n",
"print 'Output ac voltage at 1KHz Vout = ',Vout,'Vpp'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Output ac voltage at 1KHz Vout = -5 Vpp\n"
]
}
],
"prompt_number": 14
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-6, Page 717"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"Rout=75.0 #open loop output resistance(Ohm)\n",
"AVOL=100000 #open loop voltage gain\n",
"Rf=5.0*10**3 #feedback path resistance(Ohm)\n",
"\n",
"Zin_CL=Rf/(1+AVOL) #closed loop input impedance(Ohm)\n",
"Zout_CL=Rout/(1+AVOL) #closed loop input impedance(Ohm)\n",
"\n",
"print 'closed loop input impedance Zin(CL) = ',round(Zin_CL,2),'Ohm'\n",
"print 'closed loop output impedance Zout(CL) = ',round(Zout_CL,5),'Ohm'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"closed loop input impedance Zin(CL) = 0.05 Ohm\n",
"closed loop output impedance Zout(CL) = 0.00075 Ohm\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-7, Page 718"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"Vin=2 #input voltage(Vrms)\n",
"RL1=2 #load resistance (KOhm)\n",
"R1=1 #inverting input resistance R1(KOhm)\n",
"RL2=4 #load resistance(KOhm)\n",
"\n",
"iout=Vin/R1 #output current (mA)\n",
"PL1=(iout**2)*RL1 #load power for 2 Ohm (W) \n",
"PL2=(iout**2)*RL2 #load power for 4 Ohm (W) \n",
"\n",
"print 'load power for 2 Ohm = ',PL1,'W'\n",
"print 'load power for 4 Ohm = ',PL2,'W'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"load power for 2 Ohm = 8 W\n",
"load power for 4 Ohm = 16 W\n"
]
}
],
"prompt_number": 26
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-8, Page 720"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math\n",
"\n",
"Iin=1.5*10**-3 #input current(mA)\n",
"RL1=1 #load resistance (KOhm)\n",
"R1=1 #inverting input resistance R1(KOhm)\n",
"RL2=2 #load resistance (KOhm)\n",
"Rf=1*10**3 #feedback path resistance(Ohm)\n",
"\n",
"Ai=math.ceil(1+(Rf/R1)) #current gain\n",
"iout=Iin*Ai #output current (mA)\n",
"PL1=(iout**2)*RL1 #load power for 1 Ohm (W) \n",
"PL2=(iout**2)*RL2 #load power for 2 Ohm (W) \n",
"\n",
"print 'load power for 2 Ohm = ',round(PL1,2),'W'\n",
"print 'load power for 4 Ohm = ',round(PL2,2),'W'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"load power for 2 Ohm = 2.25 W\n",
"load power for 4 Ohm = 4.51 W\n"
]
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-9, Page 723"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"AB=1000 #(1+AvolB) term \n",
"f2_OL=160 #open loop bandwidth(Hz)\n",
"\n",
"f2_CL=f2_OL*AB/1000 #closed loop bandwidth(KHz)\n",
"\n",
"print 'closed loop bandwidth f2(CL)= ',f2_CL,'KHZ'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"closed loop bandwidth f2(CL)= 160 KHZ\n"
]
}
],
"prompt_number": 29
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-10, Page 723"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"AVOL=250000 #open loop voltage gain\n",
"f2_OL=1.2 #open loop bandwidth(Hz)\n",
"Av_CL=50 #closed loop voltage gain\n",
"\n",
"f2_CL=f2_OL*AVOL/Av_CL/1000 #closed loop bandwidth(KHz)\n",
"\n",
"print 'closed loop bandwidth for Av(CL) = 50, f2(CL)= ',f2_CL,'KHZ'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"closed loop bandwidth for Av(CL) = 50, f2(CL)= 6.0 KHZ\n"
]
}
],
"prompt_number": 32
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-11, Page 724"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"AVOL=50000 #open loop voltage gain\n",
"f2_OL=14 #open loop bandwidth(Hz)\n",
"\n",
"f2_CL=f2_OL*(1+AVOL)/1000 #closed loop bandwidth(KHz)\n",
"\n",
"print 'closed loop bandwidth f2(CL)= ',f2_CL,'KHZ'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"closed loop bandwidth f2(CL)= 700 KHZ\n"
]
}
],
"prompt_number": 35
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-12, Page 724"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"AB=2500 #(1+AvolB) term \n",
"f2_OL=20 #open loop bandwidth(Hz)\n",
"\n",
"f2_CL=f2_OL*AB/1000 #closed loop bandwidth(KHz)\n",
"\n",
"print 'closed loop bandwidth f2(CL)= ',f2_CL,'KHZ'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"closed loop bandwidth f2(CL)= 50 KHZ\n"
]
}
],
"prompt_number": 38
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19-13, Page 724"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math\n",
"\n",
"Av_CL=10.0 #voltage gain\n",
"Funity=1*10**6 #unity frequency (Hz) \n",
"Sr=0.5 #slew rate (V/us)\n",
"\n",
"f2_CL=Funity/Av_CL/1000 #closed loop bandwidth(KHz)\n",
"Vp_max=1000*Sr/(2*math.pi*f2_CL) #largest peak output voltage(V)\n",
"\n",
"print 'closed loop bandwidth f2(CL)= ',f2_CL,'KHZ'\n",
"print 'largest peak output voltage Vp(max)= ',round(Vp_max,3),'V'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"closed loop bandwidth f2(CL)= 100.0 KHZ\n",
"largest peak output voltage Vp(max)= 0.796 V\n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}