{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 11: Power Amplifiers" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.1: PA_Ex_11_1.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clc\n", "//Chapter 11:Power amplifiers\n", "//example 11.1 page no 456\n", "//given\n", "Po=5//max power in watts\n", "Rl=50//load resistance in ohm\n", "Vp=sqrt(2*5*50)//peak voltage across Rl\n", "Vcc=24//supply voltage\n", "Ip=Vp/Rl//peak current corresponding to Vp\n", "Iq=Vcc/50//Q point current value\n", "Pcc=Vcc*Iq//power supplied\n", "Eff=(Po/Pcc)*100//efficiency\n", "mprintf('peak voltage across Rl is %f V \n the peak current is %f A \n the power supplied is %f W \n the efficiency is %f ',Vp,Ip,Pcc,Eff)\n", "disp('the transistor that is selected must be able to dissipate 11.52W in case the input power drops to zero and the transistor Vce breakdown voltage must be at least 48V(2*Vcc)')" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.2: PA_Ex_11_2.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clc\n", "//Chapter 11:Power amplifiers\n", "//example 11.2 page no 466\n", "//given\n", "Po=5//max power in watts\n", "Rl=50//load resistance in ohm\n", "//asumme'1:1 truns ratio transformer coupled push pull amplifier each supllying 2.5 watt'\n", "disp('since a push pull amplifier is used, each class B amplifier will supply 2.5W')\n", "Pomax=2.5\n", "Vcc=sqrt(4*Rl*Po)//supply voltage\n", "Ptmax=Pomax*(4/%pi^2)//maximum power handling requriment of the transistor\n", "I=sqrt((4*Pomax)/Rl)//peak output current\n", "mprintf('maximum power handling requriment of the transistor is %d W \n peak output current is %f A ',Ptmax,I)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.3: PA_Ex_11_3.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clc\n", "//Chapter 11:Power amplifiers\n", "//example 11.2 page no 474\n", "//given\n", "Po=5//max power in watts\n", "Rl=50//load resistance in ohm\n", "f=1e6//operating frequency in hertz\n", "Vcc=sqrt(2*Rl*Po)\n", "Ptmax=0.1*Po//allowable power dissipation\n", "I_m=0.5\n", "Im=(2*%pi*Vcc*I_m)/Rl//peak collector current\n", "mprintf('required supply voltage is %f V \n max allowable power dissipation is %f W \n peak collector current is %f A',Vcc,Ptmax,Im)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.4: PA_Ex_11_4.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clc\n", "//Chapter 11:Power amplifiers\n", "//example 11.4 page no 475\n", "//given\n", "Pt=4//max power dissipation in watt\n", "Idmax=1.5//max drain current in amp\n", "Vcc=48//supply voltage\n", "P_t=(4*%pi*Pt)/(Vcc*Idmax)//the normalised max transistor dissipation\n", "disp('from figure 11.21 it is found that maximum possible conduction angle is =80degree without exceeding the maximum transistor dissipation')\n", "Po=Pt/0.22//output power\n", "Rl=Vcc^2/(2*Po)//load resistance\n", "mprintf('the output power is %f W \n the load resistance is %f ohm ',Po,Rl)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.5: PA_Ex_11_5.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clc\n", "//Chapter 11:Power amplifiers\n", "//example 11.5 page no 477\n", "//given\n", "disp('from the figure 11.23 it is seen that the amplitude of the fourth harmonic has a maximum value for a conduction angle 2theta of approximately 60degree The output circuit would be tuned to the fourth harmonic of the input signal')" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.6: PA_Ex_11_6.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clc\n", "//Chapter 11:Power amplifiers\n", "//example 11.6 page no 479\n", "//given\n", "Po=20//power delivered in watt\n", "Rl=50//load resistance\n", "Vcc=sqrt(%pi^2*Rl*Po/8)//suppy volatage\n", "Idc=4*Vcc/(Rl*%pi^2)//direct current in each transistor\n", "mprintf('the suppy volatage is %f V \n the direct current in each transistor is %f A',Vcc,Idc)\n", "disp('the maximum voltage drop across each transistor will be 2Vcc,or 70.2V the load circuit would be tuned to resonant at the fundamental frequency of the input signal')\n", "" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.7: PA_Ex_11_7.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clc\n", "//Chapter 11:Power amplifiers\n", "//example 11.7 page no 480\n", "//given\n", "Vg=8//get signal level for VMOS 2N6659\n", "Rl=50//load resistance in ohms(it should have been given in the problem but its missing)\n", "disp('The specification sheet for the 2N6659 indicates that yhe on resisitance is approximately 2 ohm for this drive level')\n", "Ron=2\n", "Poideal=20\n", "Po=Poideal*((Rl/(Rl+Ron))^2)//actual output power\n", "Eff=Rl*100/(Rl+Ron)//Efficiency\n", "mprintf('actual output power is %f W \n the Efficiency is %f ',Po,Eff)" ] } ], "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 }