{
"cells": [
 {
		   "cell_type": "markdown",
	   "metadata": {},
	   "source": [
       "# Chapter 4: Opamps with negative feedback"
	   ]
	},
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.10: Gain_and_impedence.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.10\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',5);\n",
"AOL=2*10^5;//unitless\n",
"Rio=2;//Mohm\n",
"Ro=75;//ohm\n",
"Ri=1;//kohm\n",
"Rf=10;//kohm\n",
"ACL=-AOL*Rf/(Rf+Ri+AOL*Ri);//unitless(Exact)\n",
"disp(ACL,'Exact close loop voltage gain');\n",
"ACL=-Rf/Ri;//unitless(Approximate)\n",
"disp(ACL,'Approximate close loop voltage gain');\n",
"Beta=Ri/(Ri+Rf);//unitless\n",
"SF=1+AOL*Beta;//unitless\n",
"Rif=Rio*10^6/SF;//ohm\n",
"disp(Rif,'Input impedence after feedback(ohm)');"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.11: Gain_and_Bandwidth.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.11\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',5);\n",
"Ri=2;//kohm\n",
"Rf=200;//kohm\n",
"//For 741C\n",
"fo=5;//Hz\n",
"AOL=2*10^5;//unitless\n",
"UGB=1;//MHz\n",
"ACL=-AOL*Rf/(Rf+Ri+AOL*Ri);//unitless(Exact)\n",
"disp(ACL,'Close loop voltage gain');\n",
"fodash=fo*AOL/-ACL;//Hz\n",
"disp(fodash/1000,'Bandwidth, fo_dash(kHz)');"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.12: Calculate_Gai.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.12\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',6);\n",
"Beta=0.06;//feedback factor\n",
"fo=100;//Hz\n",
"AOL=40000;//unitless(at dc)\n",
"SFdc=1+AOL*Beta;//sacrifice factor at dc\n",
"f=1;//kHz\n",
"f=f*10^3;//Hz\n",
"SF1=1+AOL*Beta/sqrt(1+f^2/fo^2);//sacrifice factor at 1 kHz\n",
"//(a)\n",
"ACL=AOL/SFdc;//(unitless)exact close loop gain at dc\n",
"disp(ACL,'Exact close loop gain at dc');\n",
"//(b)\n",
"ACL=1/Beta;//(unitless)approximate close loop gain at dc\n",
"disp(ACL,'Approximate close loop gain at dc');\n",
"//(c)\n",
"AOL=3980;//unitless(at dc)\n",
"ACL=AOL/SF1;//(unitless)exact close loop gain at 1kHz\n",
"disp(ACL,'Exact close loop gain at 1kHz');"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.13: Input_and_output_impedence.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.13\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',5);\n",
"Beta=0.04;//feedback factor\n",
"AOL=5000;//unitless(at dc)\n",
"Rio=40;//kohm\n",
"Ro=1;//kohm\n",
"SF=1+AOL*Beta;//sacrifice factor at dc\n",
"Rif=Rio/SF*1000;//ohm\n",
"disp(Rif,'Input impedence(ohm)');\n",
"Rof=Ro*1000/SF;//ohm\n",
"disp(Rof,'Output impedence(ohm)');"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.1: Bandwidth_with_feedback.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.1\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',9);\n",
"AOL=2*10^5;//unitless\n",
"fo=5;//Hz\n",
"ACL=100;//unitless\n",
"SF=AOL/ACL;//unitless\n",
"fodash=SF*fo;//Hz\n",
"disp(fodash/1000,'Bandwidth with feedback(kHz)');"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.2: Acl_Rif_Rof_fodash.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.2\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',6);\n",
"AOL=2*10^5;//unitless\n",
"Ri=1.5;//kohm\n",
"Rf=12;//kohm\n",
"Rio=1;//Mohm\n",
"Ro=100;//ohm\n",
"fo=5;//Hz\n",
"Beta=Ri/(Ri+Rf);//unitless\n",
"SF=(1+AOL)*Beta;//unitless\n",
"ACL=AOL/SF;//unitless\n",
"disp(ACL,'Value of ACL');\n",
"//In case of ideal opamp\n",
"ACL=1+Rf/Ri;//unitless\n",
"disp(ACL,'In case of ideal opamp, Value of ACL');\n",
"Rif=Rio*SF;//kohm\n",
"disp(Rif,'Value of Rif(Mohm)');\n",
"disp('This is a large value can be assumed as infity resistance.');\n",
"format('v',5);\n",
"Rof=Ro/SF;//mohm\n",
"disp(Rof*1000,'Value of Rof(mohm)');\n",
"fodash=SF*fo;//Hz\n",
"disp(fodash/1000,'Bandwidth with feedback, fo_dash(kHz)');\n",
"//Answer for Rif in the book has mistake of unit."
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.3: Impedence_and_gain.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.3\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',9);\n",
"AOL=%inf;//unitless\n",
"Rio=%inf;//ohm\n",
"Ri=1;//kohm\n",
"Rf=15;//kohm\n",
"SF=%inf;//unitless;//as SF=1+AOL*Beta\n",
"Beta=Ri/(Ri+Rf);//unitless\n",
"ACL=1/Beta;//unitless\n",
"disp(Rio,'Input impedence(ohm) for ideal opamp is ');\n",
"disp(ACL,'Gain of the circuit, ACL');"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.4: Input_and_output_impedence.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.4\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',9);\n",
"AOL=400;//unitless\n",
"Rio=500;//kohm\n",
"Ro=75;//ohm\n",
"ACL=100;//unitless\n",
"SF=AOL/ACL;//unitless\n",
"Rif=Rio*SF;//kohm\n",
"disp(Rif/1000,'Input impedence, Rif(Mohm)');\n",
"Rof=Ro/SF;//ohm\n",
"disp(Rof,'Output impedence, Rof(ohm)');"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.5: Non_Inverting_Amplifier.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.5\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',5);\n",
"ACL=200;//unitless\n",
"AOL=2*10^5;//unitless\n",
"Rio=2;//Mohm\n",
"Ro=75;//ohm\n",
"Ri=1;//kohm(Assumed)\n",
"SF=AOL/ACL;//unitless\n",
"Beta=(SF-1)/AOL;//unitless\n",
"Rf=Ri*(1-Beta)/Beta;//kohm\n",
"disp(Ri,'Input impedence, Rif(kohm)');\n",
"disp(Rf,'Feedback impedence, Rf(kohm)');"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.6: Close_Loop_Voltage_Gai.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.6\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',5);\n",
"AOL=50;//unitless\n",
"Beta=0.8;//unitless\n",
"deltaAOL=-20;//%(Change in open loop gain)\n",
"deltaBeta=15;//%(Change in feedback factor)\n",
"AOLnew=AOL+AOL*deltaAOL/100;//unitless(AOL after change)\n",
"Betanew=Beta+Beta*deltaBeta/100;//unitless(Beta after change)\n",
"ACL=AOLnew/(1+AOLnew*Betanew);//unitless\n",
"disp(ACL,'Close loop gain, ACL');"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.7: Acl_Rif_Rof.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.7\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',5);\n",
"AOL=500;//unitless\n",
"Rio=300;//kohm\n",
"Ro=100;//ohm\n",
"ACL=AOL/(1+AOL);//unitless\n",
"Rif=Rio*(1+AOL)/1000;//Mohm\n",
"Rof=Ro/(1+AOL);//ohm\n",
"disp(ACL,'Close loop gain, ACL');\n",
"disp(Rif,'Value of Rif(Mohm)');\n",
"disp(Rof,'Value of Rof(ohm)');"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.8: Output_Voltage.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.8\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',5);\n",
"Iin=1;//mA\n",
"Rf=1;//kohm\n",
"IB=0;//for ideal opamp\n",
"If=Iin-IB;//mA\n",
"Vout=-If*Rf;//V\n",
"disp(Vout,'Output Voltage(V)');"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 4.9: Variation_in_output_Voltage.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"////Ex 4.9\n",
"clc;\n",
"clear;\n",
"close;\n",
"format('v',5);\n",
"I2=1;//mA\n",
"Rf=4.7;//kohm\n",
"//Case 1st\n",
"I1=500;//micro A\n",
"Vout1=-I1*10^-6*Rf*10^3;//V\n",
"disp(Vout1,'For 500 micro A current, Output Voltage(V)');\n",
"//Case 2nd\n",
"I2=1;//mA\n",
"Vout2=-I2*10^-3*Rf*10^3;//V\n",
"disp(Vout2,'For 1 mA current, Output Voltage(V)');\n",
"deltaVout=Vout2-Vout1;//V\n",
"disp(deltaVout,'Variation in Output Voltage(V)');"
   ]
   }
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