Exemplo 4 - Filtro RC passa-baixa/Método de Euler

%IFPB 09/08/2017
%METODO DE EULER
%APLICACAO PARA ANALISE NO TEMPO DO FILTRO RC PASSA-BAIXA
clear all, close all, clc, help rclowpass_pause.m
global tal;
for N=10:5:500
    R=1E3; C=1E-6;tal=R*C;fxy='(x-y)./tal';
    a=0; b=7*tal; h=(b-a)/N;
    u=0; y0=0;
    y(1)=y0+h*funcao(u,y0,fxy);
    u=1;j=2;
    for t=a:h:b-h
        y(j)=y(j-1)+h*funcao(u,y(j-1),fxy);
        j=j+1;
    end
    t=a:h:b;
    t1=a:(b-a)/1000:b;
    yexato=1-exp(-t1/tal);
    disp([t' y']);
    t=t.*1000;t1=t1.*1000;
    set(gcf,'Position',[1 29 800 504],'Color',[1 1 1]);
    axs = axes;
    p=plot(t,y,'k.',t1,yexato,'k');
    set(p,'Linewidth',2);
    xla=xlabel('tempo(ms)');
    yla=ylabel('y(t)(volt)');
    leg=legend('METODO DE EULER','RESPOSTA EXATA',4);
    txa=text(5,0.2,['N = ' num2str(N)]);
    txb=text(5,0.15,['h=(b-a)/N = ' num2str(h)]);
    set(axs ,'FontName','TimesNewRoman','FonSize','12','FontWeight','Bold')
    set(xla ,'FontName','TimesNewRoman','FonSize','12','FontWeight','Bold')
    set(yla ,'FontName','TimesNewRoman','FonSize','12','FontWeight','Bold')
    set(leg ,'FontName','TimesNewRoman','FonSize','12','FontWeight','Bold')
    set(txa ,'FontName','TimesNewRoman','FonSize','12','FontWeight','Bold')
    set(txb ,'FontName','TimesNewRoman','FonSize','12','FontWeight','Bold')
    pause
    delete(axs);
end