path: root/Electronic_Devices_by_T_L_Floyd/10-Amplifier_Frequency_Response.ipynb

{
"cells": [
 {
		   "cell_type": "markdown",
	   "metadata": {},
	   "source": [
       "# Chapter 10: Amplifier Frequency Response"
	   ]
	},
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.10: input_RC_circuit_BJT.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.10\n",
"B_ac=125;\n",
"C_be=20*10^-12;\n",
"C_bc=2.4*10^-12;\n",
"R1=22*10^3;\n",
"R2=4.7*10^3;\n",
"R_E=470;\n",
"R_S=600;\n",
"R_L=2.2*10^3;\n",
"V_CC=10;\n",
"V_B=(R2/(R1+R2))*V_CC;\n",
"V_E=V_B-0.7;\n",
"I_E=V_E/R_E;\n",
"r_e=25*10^-3/I_E;\n",
"//total resistance of input circuit is parallel combination of R1,R2,R_s,B_ac*r_e\n",
"R_in_tot=B_ac*r_e*R1*R2*R_S/(B_ac*r_e*R1*R2+B_ac*r_e*R1*R_S+B_ac*r_e*R2*R_S+R1*R2*R_S);\n",
"R_c=R_C*R_L/(R_C+R_L)\n",
"A_v_mid=R_c/r_e;\n",
"C_in_Miller=C_bc*(A_v_mid+1)\n",
"C_in_tot=C_in_Miller+C_be;\n",
"f_c=1/(2*%pi*R_in_tot*C_in_tot);\n",
"disp(R_in_tot, 'total resistance of circuit in ohms')\n",
"disp(C_in_tot,'total capacitance in farads')\n",
"disp(f_c,'critical frequency in hertz')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.11: Critical_frequency_BJT_output.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.11\n",
"C_bc=2.4*10^-12;    //from previous question\n",
"A_v=99;    //from previous question\n",
"R_C=2.2*10^3;\n",
"R_L=2.2*10^3;\n",
"R_c=R_C*R_L/(R_C+R_L);\n",
"C_out_Miller=C_bc*(A_v+1)/A_v;\n",
"f_c=1/(2*%pi*R_c*C_bc);    //C_bc is almost equal to C_in_Miller\n",
"disp(R_c,'equivalent resistance in ohms')\n",
"disp(C_out_Miller,'equivalent capacitance in farads')\n",
"disp(f_c,'critical frequency in hertz')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.12: FET_capacitors.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.12\n",
"C_iss=6*10^-12;\n",
"C_rss=2*10^-12;\n",
"C_gd=C_rss;\n",
"C_gs=C_iss-C_rss;\n",
"disp(C_gd,'gate to drain capacitance in farads')\n",
"disp(C_gs,'gate to source capacitance in farads')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.13: Critical_frequency_FET_input.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.13;\n",
"C_iss=8*10^-12;\n",
"C_rss=3*10^-12;\n",
"g_m=6500*10^-6;    //in Siemens\n",
"R_D=1*10^3;\n",
"R_L=10*10^6;\n",
"R_s=50;\n",
"C_gd=C_rss;\n",
"C_gs=C_iss-C_rss;\n",
"R_d=R_D*R_L/(R_D+R_L);\n",
"A_v=g_m*R_d;\n",
"C_in_Miller=C_gd*(A_v+1);\n",
"C_in_tot=C_in_Miller+C_gs;\n",
"f_c=1/(2*%pi*C_in_tot*R_s);\n",
"disp(f_c,'critical frequency of input RC circuit in hertz')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.14: Critical_frequency_FET_input.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.14\n",
"C_gd=3*10^-12;    //from previous question\n",
"A_v=6.5;    //from previous question\n",
"R_d=1*10^3;    //from previous question\n",
"C_out_Miller=C_gd*(A_v+1)/A_v;\n",
"f_c=1/(2*%pi*R_d*C_out_Miller);\n",
"disp(f_c,'critical frequency of the output circuit in hertz')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.15: Bandwidth.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.15\n",
"f_cu=2000;\n",
"f_cl=200;\n",
"BW=f_cu-f_cl;\n",
"disp(BW,'bandwidth in hertz')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.16: Bandwidth_transistor.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.16;\n",
"f_T=175*10^6;    //in hertz\n",
"A_v_mid=50;\n",
"BW=f_T/A_v_mid;\n",
"disp(BW,'bandwidth in hertz')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.17: Bandwidth_2stage_amplifier.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.17\n",
"f_cl=1*10^3;    //lower critical frequency of 2nd stage in hertz\n",
"f_cu=100*10^3;    //upper critical frequency of 1st stage in hertz\n",
"BW=f_cu-f_cl;\n",
"disp(BW,'bandwidth in hertz')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.18: Bandwidth_2stage_amplifier.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.18\n",
"n=2;    //n is the number of stages of amplifier\n",
"f_cl=500;\n",
"f_cu=80*10^3;\n",
"f_cl_new=f_cl/(sqrt(2^(1/n)-1));\n",
"f_cu_new=f_cu*(sqrt(2^(1/n)-1));\n",
"BW=f_cu_new-f_cl_new;\n",
"disp(BW,'bandwidth in hertz')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.1: Gain_in_decibel.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.1\n",
"//P out/P in=250;\n",
"A_p_dB=gain_in_decibel_power(250)\n",
"disp(A_p_dB,'Power gain when power gain is 250')\n",
"A_p_dB=gain_in_decibel_power(100)\n",
"disp(A_p_dB,'Power gain when power gain is 100')\n",
"A_v_dB=gain_in_decibel_voltage(10)\n",
"disp(A_v_dB,'Voltage gain when voltage gain is 10')\n",
"A_v_dB=gain_in_decibel_power(0.5)\n",
"disp(A_v_dB,'Power gain when voltage gain is 0.5')\n",
"A_v_dB=gain_in_decibel_voltage(0.707)\n",
"disp(A_v_dB,'Voltage gain when voltage gain is 0.707')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.2: Critical_frequency.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.2\n",
"//input voltage=10V\n",
"//at -3dB voltage gain from table is 0.707\n",
"v_out=0.707*10;\n",
"disp(v_out,'output voltage in volts at -3dB gain')\n",
"//at -6dB voltage gain from table is 0.5\n",
"v_out=0.5*10;\n",
"disp(v_out,'output voltage in volts at -6dB gain')\n",
"//at -12dB voltage gain from table is 0.25\n",
"v_out=0.25*10;\n",
"disp(v_out,'output voltage in volts at -12dB gain')\n",
"//at -24dB voltage gain from table is 0.0625\n",
"v_out=0.0625*10;\n",
"disp(v_out,'output voltage in volts at -24dB gain')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.3: Lower_critical_frequency.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.3\n",
"R_in=1*10^3;\n",
"C1=1*10^-6;\n",
"A_v_mid=100;    //mid range voltage gain\n",
"f_c=1/(2*%pi*R_in*C1);\n",
"//at f_c, capacitive reactance is equal to resistance(X_C1=R_in)\n",
"attenuation=0.707;\n",
"//A_v is gain at lower critical frequency\n",
"A_v=0.707*A_v_mid;\n",
"disp(f_c,'lower critical frequency in hertz')\n",
"disp(attenuation,'attenuation at lower critical frequency')\n",
"disp(A_v,'gain at lower critical frequency')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.4: Voltage_gains.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.4\n",
"A_v_mid=100;\n",
"//At 1Hz frequency,voltage gain is 3 dB less than at midrange. At -3dB, the voltage is reduced by a factor of 0.707\n",
"A_v=0.707*A_v_mid;\n",
"disp(A_v,'actual voltage gain at 1Hz frequency')\n",
"//At 100Hz frequency,voltage gain is 20 dB less than at critical frequency (f_c ). At -20dB, the voltage is reduced by a factor of 0.1\n",
"A_v=0.1*A_v_mid;\n",
"disp(A_v,'actual voltage gain at 100Hz frequency')\n",
"//At 10Hz frequency,voltage gain is 40 dB less than at critical frequency (f_c). At -40dB, the voltage is reduced by a factor of 0.01\n",
"A_v=0.01*A_v_mid;\n",
"disp(A_v,'actual voltage gain at 10Hz frequency')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.5: Output_RC_circuit.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.5\n",
"R_C=10*10^3;\n",
"C3=0.1*10^-6;\n",
"R_L=10*10^3;\n",
"A_v_mid=50;\n",
"f_c=1/(2*%pi*(R_L+R_C)*C3);\n",
"disp(f_c,'lower critical frequency in hertz')\n",
"//at midrange capacitive reactance is zero\n",
"X_C3=0;\n",
"attenuation=R_L/(R_L+R_C);    \n",
"disp(attenuation,'attenuation at midrange frequency')\n",
"//at critical frequency, capacitive reactance equals total resistance\n",
"X_C3=R_L+R_C;\n",
"attenuation=R_L/(sqrt((R_C+R_L)^2+X_C3^2));\n",
"disp(attenuation,'attenuation at critical frequency')\n",
"A_v=0.707*A_v_mid;\n",
"disp(A_v,'gain at critical frequency')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.6: Bypass_RC_circuit_BJT.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.6\n",
"B_ac=100;\n",
"r_e=12;\n",
"R1=62*10^3;\n",
"R2=22*10^3;\n",
"R_S=1*10^3;\n",
"R_E=1*10^3;\n",
"C2=100*10^-6;\n",
"//Base circuit impedance= parallel combination of R1, R2, R_S\n",
"R_th=(R1*R2*R_S)/(R1*R2+R2*R_S+R_S*R1);\n",
"//Resistance looking at emitter\n",
"R_in_emitter=r_e+(R_th/B_ac);\n",
"//resistance of equivalent bypass RC is parallel combination of R_E,R_in_emitter\n",
"R=(R_in_emitter*R_E)/(R_E+R_in_emitter);\n",
"f_c=1/(2*%pi*R*C2);\n",
"disp(f_c,'critical frequency of bypass RC circuit in hertz')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.7: input_RC_circuit_FET.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.7\n",
"V_GS=-10;\n",
"I_GSS=25*10^-9;\n",
"R_G=10*10^6;\n",
"C1=0.001*10^-6;\n",
"R_in_gate=abs((V_GS/I_GSS));\n",
"R_in=(R_in_gate*R_G)/(R_G+R_in_gate);\n",
"f_c=1/(2*%pi*R_in*C1);\n",
"disp(f_c,'critical frequency in hertz')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.8: Low_frequency_response_FET.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.8\n",
"V_GS=-12;\n",
"I_GSS=100*10^-9;\n",
"R_G=10*10^6;\n",
"R_D=10*10^3;\n",
"C1=0.001*10^-6;\n",
"C2=0.001*10^-6;\n",
"R_in_gate=abs((V_GS/I_GSS));\n",
"R_in=(R_in_gate*R_G)/(R_G+R_in_gate);\n",
"R_L=R_in;    //according to question\n",
"f_c_input=1/(2*%pi*R_in*C1);\n",
"disp(f_c_input,'critical frequency of input RC circuit in hertz')\n",
"f_c_output=1/(2*%pi*(R_D+R_L)*C2)\n",
"disp(f_c_output,'critical frequency of output RC circuit in hertz')"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 10.9: Low_frequency_response_BJT.sce"
		   ]
		  },
  {
"cell_type": "code",
	   "execution_count": null,
	   "metadata": {
	    "collapsed": true
	   },
	   "outputs": [],
"source": [
"//ex10.9\n",
"B_ac=100;\n",
"r_e=16;\n",
"R1=62*10^3;\n",
"R2=22*10^3;\n",
"R_S=600;\n",
"R_E=1*10^3;\n",
"R_C=2.2*10^3;\n",
"R_L=10*10^3;\n",
"C1=0.1*10^-6;\n",
"C2=10*10^-6;\n",
"C3=0.1*10^-6;\n",
"//input RC circuit\n",
"R_in=(B_ac*r_e*R1*R2)/(B_ac*r_e*R1+B_ac*r_e*R2+R1*R2);\n",
"f_c_input=1/(2*%pi*(R_S+R_in)*C1);\n",
"disp(f_c_input,'input frequency in hertz')\n",
"//For bypass circuit; Base circuit impedance= parallel combination of R1, R2, R_S\n",
"R_th=(R1*R2*R_S)/(R1*R2+R2*R_S+R_S*R1);\n",
"//Resistance looking at emitter\n",
"R_in_emitter=r_e+(R_th/B_ac);\n",
"//resistance of equivalent bypass RC is parallel combination of R_E,R_in_emitter\n",
"R=(R_in_emitter*R_E)/(R_E+R_in_emitter);\n",
"f_c_bypass=1/(2*%pi*R*C2);\n",
"disp(f_c_bypass,'critical frequency of bypass RC circuit in hertz')\n",
"f_c_output=1/(2*%pi*(R_C+R_L)*C3)\n",
"disp(f_c_output,'output frequency circuit in hertz')\n",
"R_c=R_C*R_L/(R_C+R_L);\n",
"A_v_mid=R_c/r_e;\n",
"attenuation=R_in/(R_in+R_S);\n",
"A_v=attenuation*A_v_mid;    //overall voltage gain\n",
"A_v_mid_dB=20*log10(A_v);    \n",
"disp(A_v_mid_dB,'overall voltage gain in dB')"
   ]
   }
],
"metadata": {
		  "kernelspec": {
		   "display_name": "Scilab",
		   "language": "scilab",
		   "name": "scilab"
		  },
		  "language_info": {
		   "file_extension": ".sce",
		   "help_links": [
			{
			 "text": "MetaKernel Magics",
			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
			}
		   ],
		   "mimetype": "text/x-octave",
		   "name": "scilab",
		   "version": "0.7.1"
		  }
		 },
		 "nbformat": 4,
		 "nbformat_minor": 0
}